Generally, I'd defer to DTN, but I want to at least give my thoughts on the examples provided.
later nerds
outplayed
These two lines I don't imagine would be an issue. The former is a very diluted/denatured insult, and, while like DTN said, might still be an issue due to the intent to aggravate. The latter, while not banter in general, is still generally mild BM. On its own, I don't think it would cause problems.
get fucked
lmao trash
git gud
sit kid
cya loser
smd
GET OFF MY SCREEN
bitch please
camp more idiot
better jg/mid/top/ad/sup wins
lol fuck you
These, I can easily see raising flags with the IFS. The first is needlessly aggressive and inflammatory, the second is an open insult, the third is moderately inflammatory, the fourth is a moderate insult - which isn't quite so denatured as "nerd", by the way - "loser" is obvious as an insult, the initialism is vulgar and inflammatory, telling someone "get off my screen" is pointless and aggressive, "bitch please" is likewise pointless and inflammatory, "camp more idiot" is another open insult, "better x wins" is needlessly aggressive, and do I really need to say that "fuck you" is neither banter nor acceptable?
Further, I should also mention that calling any of the examples "banter" would be a misnomer. Banter is friendly and light-hearted, and none of these examples fit that description.