To show just how crazy things can get, check out this tweet by a D congressman. While an extreme request, I do think Pelosi could make a rational argument that anyone who signed on to that list AND came from a state under contest, is by extension, contesting their own victory.
So in a world where SCOTUS did lock up those states electoral votes, seemingly sending the election to the house, she'd have a pretty rational case not to seat that specific subset of representatives. I don't know the math, but if that subset was enough to ensure PA/MI/WI/GA delegations had D majorities, that would give her perfect cover to flip the house vote to Biden.
This is messy AF but is the kind of crap we should expect in the event Trump was (somehow) successful.