Nathanos has been created in a more realistic soldier type of character. A pretty good soldier and an effective operative.
But Thrall is one of those plot power houses that wields the cosmic energies of the whole planet and blah blah blah…
Don’t want to get into my personal bias regarding how I feel about said kind of characters, but they are indeed written to be extremely powerful.
They must, as they are often given roles of supreme command over world ending threats, soloing entire evil armies, and all that drivel.
Yeah, I rather they had stayed with Thrall the Lord of Clans, and left Go’el the World Shaman out.
But definetly, current Thrall would easily own most of the more grounded and “realistic” (as realistic as an upgraded undead can be) characters such as Nathanos.
(Tbh, what I said about Go’el applies to Tyrande, Malfurion, Jaina, BfA Sylvanas, etc.)