We highly recommend you do not do this.
This is a very new field, and to many unknowns. As well Amazon has took down some books, that had art done by AI on them. No way to know for sure if that is the reason or if there was other reasons, since KDP rarely says detailed things about books. As of this FAQ they have not made known a view on this, that we know of.
There is at least one lawsuit that has started from Artists to these AI Generated art places, because the AI learns off of art and images that is out. There probably will be more lawsuits down the road if not already.
As well, even if Amazon said it was okay to use, if you emailed them say. That will not cover you for life, they may change their mind, they may pull books off their website down the road, they may decide to ban people. In the end, no one knows, be safe and do not use AI generated art.