Antonym of nomad

If you're speaking of historical populations, you might use the word "settler".

A resident may convey the idea of someone who lives permanently in the same place:

• One who resides in a particular place permanently or for an extended period. (AHD)

or an inhabitant:

• One that inhabits a place, especially as a permanent resident: the inhabitants of a fishing village; snakes, lizards, and other inhabitants of the desert.

@Eilia's comment pretty much hits the mark. According to Merriam-Webster sedentary means (among others):

staying or living in one place instead of moving to different places

Or more pronounced yet:

1: not migratory: settled (sedentary birds) (sedentary civilizations)

Aside from sedentary the antonyms and near antonyms listed for migrant might be interesting as well.

Here in Ireland, there is a community which is traditionally nomadic: they are known by various names, but usually as The Travellers (in the UK, they are known as Irish Travellers, and recognised as an indigenous minority ethnic group). RTÉ, the state broadcaster, will refer to “members of the Travelling community”. The rest of us, by contrast, are known as the Settled community. (We are not called settlers, which to me invokes images of arriving at a place and settling there. I didn’t settle here: I was born here.)