The Nasen quest is current the end cap mission for that route for now. For Winston to trust you, I believe you’d have to achieve the peace ending in Greyfold
The Nasen one is an infinite money glitch so enjoy it while it lasts haha, for Winston, you gotta help him out and tell him you're not a Slaver. If he ever catches you while you're out getting Slaves then he'll no longer trust you and you wont see him in his hideout at Greyfold anymore.
