Now Kabuto can heal, Nagato abilities has no way of physically damaging Kabuto. Though, Kabuto's perception abilities and reflexes dramatically increase, can it be enough to avoid Nagato's "Shared Vision" (Rinnegan)? I think not. Nagato's "Shared Vision" is enough to trap Kabuto into a corner to at least get close for him to utilize Preta Realm abilities to take souls. If by chance these can happen then Nagato have everything he needs to win the battle. However, it could go either-way, because less is still known about Kabuto of what he could display in Sage Mode.