in general playing tight isn't really ideal, especially at micros, even if you get called a lot they will fold so often postflop that it's just so profitable being on the looser side of things.
Nash is rarely ever good in these games, you are simply missing out on a ton of spots by playing NASH. It's sort of defensive last resort way to play if players cannot be exploited, so while you will not make as many mistakes, you also cannot take advantage of other players mistakes. I'm going to link you to a post that might help and what i suspect you are going through, it's so easy to over adjust from shoving a loose range when you get a few loose calls, however adjusting may not be your best bet, any time you have to adjust to a tighter strategy it makes me worried, as blinding out is the worst thing you can do in these games.
One last thing, non all in preflop plays in micros work, really, reaaaaly well. So try stuff like limp/jamming (with appropriate stack sizes). or raising half your stack and shoving flops, fish love to see flops and don't care how much they have to call to do so, but once they miss they tend to give up really easily, so take advantage of this general tendency. I do these plays with hands that may or may not be straight up profitable to shove preflop, if a hand is good enough to shvoe for x amount of BBs then it's usually better off straight jammed. But if you have to make one of these "-ev" shoves, then trying these things may give you a little more FE
hope this helps