Nocturne and Master Yi. they may not be at their bests during a 5v5 match, but Twisted Treeline is more solo oriented. the only feeding there is is if you screwed up early in the game or you are really hellbent in not team cooperation, which are downfalls for yi and nocturne who have little defense and atk to start off with, not to mention feeding summoners give big advantages over these guys. but if done right, yi can start killing summoners early with teamwork or luck, then start using his ulti, run down one summoner, refill skills, use E to heal, taking little damage due to the armor u get, ulti, kill another champ, E, ulti, triple kill ace. at this point if u can get an ace by yourself the game is won.
now to Nocturne. starting off with a atk spd shoe will guarantee ur speed greater or equal to enemy champs, so deaths are lessened and kills are easier flat out. then u wanna start on either infinity blade or the tiamat cleaver(?). atk spd is last on the list cuz ur gaining atk speed anyways from lvling E, so your doubly increasing your lethality. until u start getting pickaxes or bfgs, u should stick with another summoner, but once u get ur sword or axe, start initiating combat since your atk should be really high for an early game. nightmare the enemy asap, use ur shield if u think they gonna use an atk, and use Q to make sure u got a trail on them. this pattern is to ensure your prey cant escape, and if he tries to your already faster than him and can easily trail. once you have your ulti, if he flashes away or uses ghost, wait for the ghost to enter cooldown or if he flashed get your ulti ready and just click on him and continue to hack. easy kills. then combine with life steal axe and a life steal lantern and focus on health and defense so you can just feel that much more powerful hacking soullessly at your enemies life.