Warriors die horribly without doing anything and are a waste of points, or last until the end of the game. Obviously it all depends on the army you're facing, but my point is there is no middle ground. Either they explode because of Insta-Death or they just never go down to small arms fire. You'd be better off with small squads and make sure to play musical warriors so that the lead isn't the one about to die as the wounds start to stack. It's harder to kill two units of three than it is one unit of six. Warriors are unique in that aspect.
For the Tyrant, look at the Tyrant Node Formation instead of a CAD with a Tyrant and Guard. This gives you room for two Flyrants or whatever other HQs you might want for this and the Walking Tyrant with minor buffs. Alternatively, look at the Hypertoxic Node Formation with a Toxicrene, three Venomthropes and a Tyrant. CAD the Guard, slap the Venom Tyrant in there and there ya go. Again, this frees up Elite slots and the HQ, and you'll need those Venomthropes. If you're playing a bunch of things that keel over to the vast majority of decent shooting, you are going to need that Cover save. Nids lack of Eternal Warrior and lack of good armor means you have to get that save another way.
Keep in mind the rest of the Formations. If you like Warriors, then most of them will be something useful to you. Bioblast, Living Artillery, Synaptic Swarm, the ones I mentioned above, they all give minor buffs to big models to make them just a shade more acceptable. There's a good chance that you'll end up using up all your HS or Elite slots otherwise and most of the models in the Formations, so these are great 'cheats' to the Force Org.