I rarely run my nids without a squad of stealers, and stealers with toxin are ridiculously awesome, since you get rerolls to wound and therefore more rending hits. Having stealers in reserves to outflank tends to keep your opponent off the board edges as well if they have ever seen them come in and eat a squad before.
Zoanthropes have an awesome attack, but are way too easy to tarpit in
CC since they only have 1 attack. Pretty much any unit in the game can assault them and survive the whole game in
CC, denying your psychic attacks. Add that to the fact that psychic hoods mean you have to pass yet another check to hit meaning you have to roll off for hood, then pass psychic check, then roll to hit, then roll to penetrate, then roll for damage and your odds of failing a check get a lot better.
Unfortunately your current list has no other option to handle
av 14, thats generally the monstrous creatures jobs. I usually use a flyrant for that purpose, plus I made a flyrant that I think looks kick ass