Since Regigigas has a horrible ability then is there a move to eliminate that in a single battle?
No, there isn't a move that can evade the effect of an Ability, Especially on Regigigas and its bad ability. Another example would be the worst ability available:Truant. There is no move that surpasses the ability. Hope this helps...
Unless the pokemon gets hit by gastro acid, there is no way it can evade the ability.Gastro acid is baton passible.