According to Duns Scotus, it is not possible to infer divine immensity from divine omnipotence:

It seems that omnipotence is the ground for acting on anything (ratio agendi in quodcumque), and for producing whatever is possible, even if per impossibile [God] were not everywhere – and according to this a negative answer to the question should be given [namely, that God’s omnipotence does not necessarily entail that he is everywhere according to his essence].1