Moody causes the Pokémon to raise one of its stats by two stages, while another stat is lowered by one stage at the end of each turn. These stats include accuracy and evasion. Moody will not attempt to lower a stat at -6 or attempt to increase a stat at +6. -Bulbapedia
The answer is no, Moody has absolutely nothing to do with priority.
And if you were thinking of Prankster, Roar / Whirlwind have -6 priority, and prankster only increases priority by + 1, so you would still be at -5 priority, meaning you wouldn't outspeed pretty much anything.
