Napoli and Inter are in a stressful situation, because ahead of the match in the UEL for Napoli who will play against Barcelona and also Inter who will play in the UCL against Liverpool. Of course, their coach has a tough job this time around, because if the player rotation isn't done properly they won't be able to play well in either of them. But even so, usually they will just forget for a moment the next match and only focus on the current match. That means, I believe they will continue to play their main squad in this match because this match is also an important match for their position at the top of the Serie A standings.
I don't think rotation will happen in such an important match like today for Inter and Napoli. Winning is very important for both teams and I'm sure both teams will try to keep playing their best players to win the match. UCL and UEL are also important, but they must not lose focus for today's Serie A.
It doesn't make sense to rest important players in this match just because they will be playing in European competition in the coming days. The preparation of players can still be expected after today's match is over and they can focus on UCL and UEL. If Inter lose then Napoli and AC Milan will be very advantaged to occupy the top of the standings, so there is no other way for Inter and Napoli to win the match unless they play all their best players in this match.