I have already unlocked the +1 movement mech upgrade. I take one of my workers inside my mech, I use one of my movements for move this mech with the worker inside to a place where already are an enemy mech. I know my mech cant move more, cant use this +1 movement upgrade, need stay there and resolve the fight. But the question is, I have still one more movement for whatever other of my units before resolve that, so can I (with this other second movement) move this worker that was "inside my mech" out from this spot to other spot?
No. The worker cannot leave a territory controlled by an enemy Mech. The rulebook says:
If your character or mech move into a territory controlled by an opponent’s character and/or mechs, its movement ends (even if you have a mech ability that would allow it to move further). The opponent still temporarily controls that territory. After you’ve completed all Move actions, if any of your mechs or your character share a territory with an opponent’s character or mechs, combat happens (see Combat section, pages 22-23).
Your workers cannot move by themselves into or out of territories controlled by opponent characters and/ or mechs.