Do protistas have nucleus?

Yes and no. The reason for this answer is that every organism that is not classified as an animal, plant, fungus, or bacteria is classified into the kingdom or "Protista". Protists can be extremely small, unicellular, microscopic organisms. Or protists can be extremely large organisms, such as giant kelp. So, all in all, yes protists do have nuclei, but not all of them. Hope that helps! They are either eukaryotic or prokaryotic so its yes and no