Your substitution of the phrase "in God's nature" for "God says so" is a simple regress that leaves us in the same position with a second question:
"Is it in God's nature Because God says so, or does God say so because it is in his nature."
If the latter, then, as before, God is not omnipotent and there are higher laws/powers directing it. If the former, then, again, God is arbitrarily choosing what his nature will be so it is moral and the morality is arbitrary. We now have the same dilemma. This cannot be ignored because it is an assertion you are making to answer the question, and therefore you need to explain all aspects of your assertion.
"Is it in God's nature Because God says so, or does God say so because it is in his nature."
If the latter, then, as before, God is not omnipotent and there are higher laws/powers directing it. If the former, then, again, God is arbitrarily choosing what his nature will be so it is moral and the morality is arbitrary. We now have the same dilemma. This cannot be ignored because it is an assertion you are making to answer the question, and therefore you need to explain all aspects of your assertion.
"Listen, strange women lying in ponds distributing swords is no basis for a system of government! Supreme executive power derives from a mandate by the masses, not some farcical aquatic ceremony!"
- Dennis the peasant.
- Dennis the peasant.