I made 2nd house but now nurse has comeThe housing list in the screenshot shows that there's no Guide alive in the world, so you wouldn't be able to do anything with him anyway. If the Merchant spawned first and took the house, the Guide won't be able to return until there's a house that's available. Try building a second house and make sure it's valid. Each NPC requires his or her own house.
i'm playing as modded i dont need themJust make the houses. You'll need them eventually anyway.