Chris Brown-- Asthma Schmazma ... My Baby Mama's a Greedy B

Chris Brown is calling BS on his baby mama ... saying she's making him look like a bad dad just to line her pockets with more of his money.

Nia Guzman claims Chris and his buddies have been smoking weed and cigarettes around 1-year-old Royalty and the second hand smoke has given her asthma. Chris posted but then deleted an Instagram post which said, "I quit cigarettes on New Years. NO ONE smokes around my daughter."

Chris did not mention weed in the post.

He does say it's "obviously a play to get some sort of increased income." On that front, he seems to have a point ... Nia wants an enormous increase in child support -- from $2,500k a month to $16k a month.

Chris ended by saying, "I take care of my daughter and I would never ever put her in a position that will harm her."