Incorrect to say. He has made a general claim, and he has not produced evidence to date. Let me guess — you are hoping he can prove it. It’s ok to express your hopes and wishes. Just say, “I sure hope that Nunes proves that Obama spied on Trump.” You are entitle to express your hopes.
But as yet there is no proof of anything on surveillance of Trump — only suspicion — and only among a handful of far-right idealogues.