I have a feeling the first part of the episode might deal with that. Either Tommy gets Nick kicked out of the frat, or there's going to be a group discussion like the last episode where there'll be a vote for if he gets the boot, and a discussion about the possible traitor.
Given how as we discussed before and Nick is being a least portrayed to be the Traitor, getting him out of the frat, would certainly add some more fuel to the fire.
A lot depends on how Vinny actually left. He and Tommy didn't get along, but if he simply dropped out of college and stayed out of Quinn's turf until he lost the Pink Rose customers, then I'd say Nick has only tried to keep a friendship alive and maybe rebuild a burned bridge. If Nick has done something wrong it was unwittingly. He's told Vinny about what has been going on with the DIKs and doesn't realise how bad a person he is now.
It could be that the falling out between Vinny and the DIKs was a lot nastier and Nick is straight up helping him get revenge, but I don't really get that vibe.
Either way Vinny is the actual traitor and Nick is just being used.
But whenever that comes up I'd expect the Heather situation to happen first. On some morning in the near future (probably episode 11, but definitely before season 4) Heather is going to join the DIKs for breakfast after fucking Nick the previous night (or MC if you play the Others path that way) and Tommy will flip.
In general I'd expect the other guys to feel that Tommy acts like the DIK motto is "Tommy comes first" instead of "Family comes first", but do any of them have the balls to actually say that? Maybe the one to throw that in Tommy's face would actually be Heather. I'd kind of expect this to become a major choice for how MC reacts in the situation. DIK option: mock Tommy over it. Neutral option: say that Tommy is reaping what he has sown but diplomatically. Chick option: try to calm things down.
There's a lot of ways the situation can play out, but personally I really want Tommy to be told off about his shit and it might be the most effective if it comes from Rusty.