Nidificant is a rarely used word, which means "building a nest." However, if you are looking for synonyms to use in place of nidificant, you can consider words such as nest-making, nest building, burrowing, and denning. Other possible synonyms are construct, create, fabricate, and assemble. Depending on the context, synonyms like habitation, dwelling, and homestead can also be used. Additionally, some nature-specific terms like beekeeping, bee-hiving, and honey-making can also be considered. All in all, there are many options to choose from when searching for synonyms for the word "nidificant".