Watering help!!!

I have about six indoor plants and recently I’ve had some gnats. I did a little bit of research and I found out because of the top layer of soil getting wet the gants like to stay there . (I’m not sure if this is right lol that’s what Google said)
What I’m going to do is taking the nursing pot out of my ceramic pots and letting the water drain upwards. The only problem with this is I didn’t know I had to keep the nursing pots in so my plant is only in ceramic pots with no drainage. I know it’s really bad. Am I doing the right thing or is there anything I could be doing better?