Why does my chicken taste like toilet water?

I was making a chicken taco cerole...I cut up onions and tomatoes and started to cook them in a pot of er. Later I added some boneless skinless chicken which had been in a bowl of salt water for like...5 or so minutes. while all that good stuff is cooking together I add salt and pepper and some salsa to the mix. When I tried a piece it tasted...funny. Not terrible or old or anything it just...like I know chicken is not supposed to taste like that. Also I am clearly not a chef so can someone tell me what it is I did wrong? An extra 10 pts for anyone who comes over and just cooks for me ;-)