The third weight is arguably the only men's weight where four different nations have a somewhat realistic gold medal chance, as far as I can tell.
Of course first off it's Shi Zhiyong who, whatever the real reasons are, keeps Liao Hui off the team. Reigning world champion, 352 at Chinese nationals this year and 348kg later on in the year while being a couple kilograms overweight.
I'd definitely think he is the man to beat, and if someone is going to be able to do that, the first one that comes to my mind is Russian Oleg Chen. World silver in 2011, 2013 and 2015 so you'd say he's about ready to take it to the next level, though his 342 and 344 of last year suggest he's more likely to lose against Shi, as is probably no surprise.
Daniyar Ismayilov could have provided Turkmenistan with their first ever Olympic medal since gaining independence, but unfortunately he is one of the many, many athletes across all sports who has chosen to represent Turkey instead. 343 last year, which suggests he is well in the hunt for the medals. Same goes for Kim Myong-hyok, the North Korean whose 342 got him 4th place at worlds last year.
Last but not least, there's a few guys waiting to pick up those medals if a couple of the aforementioned should fail. Most notable I'd say Colombian Luis Mosquera, Mexican Bredni Roque and the ever-improving Kyrgyz Izzat Artykov. Their best ever Olympic weightlifting finish is an 11th place, so it'd be quite cool if Artykov can win a medal for Kyrgyzstan if you ask me.
My top-5:
1. Shi
2. Chen
3. Ismayilov
4. Kim
5. Artykov