Using sp_BlitzIndex - Diagnosed as "Index Hoarder: Addicted to nulls"
I think the script in question is sp_BlitzIndex.

The script lists tables that have more than 3 columns, and the number of non-nullable columns is 1 or 0. It doesn't mean that those tables are bad-- but if you see a lot of rows for this, it's just there to raise the question: 


Is it valid for those columns to all really contain nulls? 
When tables are created, are people being careful to set the right
properties?


If the answer to both of those questions is yes, then it's totally fine. The check is just there because it's worth thinking about. It's in there mostly just for starting conversations about data integrity and validity, that's all.

Thanks for using the script!