Answer;
Kingdom Eubacteria
A unicellular kingdom that does not have a nucleus would belong in the kingdom Eubacteria.
Step-by-step explanation;
Kingdom Eubacteria is the kingdom of prokaryotic, single-celled organisms that lack a membrane-enclosed nucleus and can be classified by shape.
Prokaryotes are organisms that lack nucleus and other membrane bound organelles, such as mitochondria. Unicellular means that the organism is made of one cell.