Games like Nigredo
Games like Nigredo include Oxygen Not Included, RimWorld, Frostpunk, Prison Architect, and Manor Lords. We matched them by the tags players give Nigredo on Steam (Time Management, 2D Platformer, Real Time Tactics, City Builder, and Colony Sim): closest matches first, and among equally close ones the better-known games.

Oxygen Not Included
Shared: Colony Sim · Survival · Base Building

RimWorld
Shared: Colony Sim · Survival · Base Building

Frostpunk
Shared: City Builder · Survival · Colony Sim

Prison Architect
Shared: Colony Sim · Building · City Builder

Manor Lords
Shared: City Builder · Base Building · Strategy

Kingdoms and Castles
Shared: City Builder · Colony Sim · Management

Dwarf Fortress
Shared: Colony Sim · City Builder · Base Building

Against the Storm
Shared: City Builder · Base Building · Strategy

Banished
Shared: City Builder · Colony Sim · Survival

Space Haven
Shared: Colony Sim · Survival · Base Building

Going Medieval
Shared: Colony Sim · Base Building · City Builder

Timberborn
Shared: City Builder · Colony Sim · Management

Settlement Survival
Shared: City Builder · Colony Sim · Management

Empires of the Undergrowth
Shared: City Builder · Colony Sim · Base Building

Endzone - A World Apart
Shared: City Builder · Survival · Colony Sim

Workers & Resources: Soviet Republic
Shared: City Builder · Base Building · Strategy

They Are Billions
Shared: Colony Sim · Base Building · Survival

Infection Free Zone
Shared: City Builder · Base Building · Management

Planetbase
Shared: City Builder · Colony Sim · Base Building

Ostriv
Shared: City Builder · Colony Sim · Management

Stronghold Crusader HD (2012)
Shared: Real Time Tactics · City Builder · Colony Sim

Norland
Shared: City Builder · Colony Sim · Management

Ratopia
Shared: Colony Sim · Building · City Builder

IXION
Shared: City Builder · Colony Sim · Survival