Chris Brown Royalty Visits Now Monitored ... Baby Mama Blew Whistle

Chris Brown's baby mama is fed up with all the drama in his life, so much so ... she dimed him out to DCFS.

Sources close to Nia Guzman told TMZ ... she filed the complaint with DCFS some time after Chris was arrested for allegedly pulling a gun on Baylee Curran -- and that's exactly why child services went to Chris' house yesterday.

We're told Nia's worried about 2-year-old Royalty's safety -- although she was NOT in the house during the alleged gun incident. Our sources say Nia thinks he's a good dad on his own, but he continues to hang with a bad crowd.

Since Chris' arrest, all of his visits with Royalty must be supervised by his mother ... at least until the case is settled.

TMZ is told Nia isn't fighting to reduce Chris' custody at this point, but she agrees monitored visits are best for now.

-TMZ