Here's how I would formulate the main tenets of Theistic Moral Nihilism:
(1) There are no moral facts or truths.
(2) There exists divine imperatives and statements of the divine will/desire.
(3) God has annexed various effects (whether by promise, providence, or creational constitution) to various actions.
(4) "Good" can be reduced to whatever satisfies one's subjective desires.
(5) The referent of "good" in (4) is relatively stable and homogenous enough because of how God made humanity to generally desire the same set of objects, although because of sin they obviously sometimes do not to their own destruction.
(6) Axiological language can be reduced to instrumentalist/prudential means-ends reasoning, e.g. if you want X goodies, you need to do B acts because God promised X upon B, etc.
(7) All language concerning righteousness can be reduced to obedience to divine commands.
( 8 ) There is no deductive answer to someone who chooses and desires death to say that that's "not good", that is, you cannot give deductive reasons for why death is not good nor should not be desired. You can only rhetorically persuade that person not to desire death by appealing to other things that person does desire which would contradict the desire for death. One cannot "jump out" of the universe of desire to reason towards a rational basis for desiring.
(9) The only response to the obstinately willful is to just give them what they want, not argue them out of it.
(10) If God does not exists, all things are permissible.
For an interesting philosophical article on this thesis, see here.