Are Fungi Sporangium haploid or diploid?

Sporangiospores are spores that are produced in a sporangium (plural: sporangia). A sporangium in fungi (but not mosses and some other organisms) is simply a cell containing spores.

The important point is that a sporangium is a cell that encloses its spores until they are mature and ready for dispersal.

In all cases if reproduction is by means of sporangiospores, spores borne inside sporangia that were the site of of diploid nuclei.