I randomly got Gnar in an ARAM and had a load of fun with him so I decided to start running him on the Rift.

I'll likely have more to say about Gnar as time goes on, but this is just my initial impression of the few match-ups that I have faced.

Akali - Not a fan of this match-up. At 21-9-0 with MR glyphs, she chunks you for a one bar of health every time she hits you with a Mark of the Assassin. And you definitely do not want to let her proc the mark. In the early lane you can kite her somewhat, but once she gets Shadow Dance forget about kiting. The lane isn't a total stomp for her, but it is precarious for you. You can probably kill her with jungler help, especially if you can time your Mega Gnar form with the gank, but if either you or your jungler are low then abort as she is probably just going to turn the gank into a double kill and then you are screwed from that point on. Build into an early Hexdrinker and then follow-up with Randuin's Omen as she does mixed damage.

Singed - I'd like to try this lane again as I only managed to go neutral in this match-up my first time. I think starting Boots or a Long Sword might be better than a Doran's Blade. You want to avoid having Singed Fling you into Poison Trail, so positioning in lane is really important. You should be able to kite singed into the dirt, but watch if he gets tricky and drops Mega Adhesive at the spot you are likely to Hop to while trying to stay out of his grasp.

For this match-up I need to continue to improve my kiting, whether that be aggressive orbwalking to stay just ahead of my lane opponent or while continuing to do damage while disengaging. May try attack move click again an sometimes, especially with shorter ranged champions like Gnar I still fubar the attack move though this is sometimes just the result of creep block.

Xin Zhao - this match-up has the potential to be a pain if he can come up with a way to stick to you. Start Cloth Armor and 5 Health Potions. You'll be working your way into a Randuin's Omen as your first item. The really dangerous spot in this lane should be at level two assuming he has leveled Audacious Charge and Three Talon Strike and has his Flash. What will generally happen is that he will dash onto you with Audacious Charge and then try and knock you up with Three Talon Strike, which has the potential to chunk you pretty good. Knowing that it is the third strike of Three Talon Strike that will knock you up, a lot of people will Flash the third strike. Good Xin's know this and will immediately Flash after if they feel like they have kill potential.

So your job is to use Hop to disengage when he jumps on you with Audacious Charge and hope their jungler isn't also coming in from a different angle (super important to have your Tri-Bush pinked if you are red side) as Hop doesn't take you that far away unless you bounce off of something and it is on a long cooldown.

At the same time you want to try and toss Boomerang Throw back at Xin to damage him and slow him down. If you hit him with it then turn around and try to get two more hits on him in order to get a Hyper proc while his dash is down.

Given that he has sustain built into Battle Cry you probably will not kill him without help from your jungler unless he over commits to a fight.

Also (and this goes for any match-up) be cognizant of your rage bar both as Mini and Mega-Gnar. I ended up dying to the Xin I was facing once because I turned back into mini-Gnar right as I was about to GNAR! him into a wall.

Cho'Gath - you have to be very careful in this lane as a slight misstep is liable to get you eaten. It may seem weird, but start with a Long Sword and three Health Potions and max Boomerang Throw first. You first item should be a Phage. The point of this is that you pretty much don't want to fight Cho directly especially after he hits 6th level and gets Feast as prehistoric yordles are totally on Cho's menu. You want to stay out of range of Feral Scream or at least far enough back that you can walk away from him because A) it hurts and B) it nullifies your ability to disengage. Simply poke him with Boomerang Throw when you can and only follow up if Feral Scream and Rupture are on cool down. Jungler help is a good idea. The lane is winnable, but it isn't easy. Note that he can interrupt Hop or Crunch with Rupture if he times it right.

After a few games with Gnar I'm thinking I may opt into a Phage into a Black Cleaver on Gnar against practically all comers. The bonus attack damage, health, cooldown reduction, stacking armor reduction, and bonus movement speed on dealing damage or getting kills and assists just meshes with Gnar's kit better than any of the other available options besides Trinity Force and tBC costs 700 less gold and there are no wasted stats.

The Rage passive from Phage specifically makes it possible for you to be much more aggressive when you have windows of opportunity.

I say practically because there are certain laners like Xin Zhao who have a dash that can negate your ability to kite. In such cases you want to itemize against the damage they are guaranteed to deliver when they dash to you. E.g. in Xin's case that is going to be a mix of magic damage from Audacious Charge and at least one to two empowered autoattacks via Three Talon Strike which does physical damage. Xin can technically build AD or AP, though AD is more common, so over time he is likely to do be doing quite a bit more physical damage than magic damage especially because Challenge reduces armor by 15%, which means more of his physical damage will get through your defenses.