Kelis Says Nas' Child Support Isn't Cutting it Anymore

Nas needs to open his fat wallet a lot more now to support his kid ... at least that's what Kelis is gunning for.

Kelis just filed legal docs saying $8k a month ain't cuttin' it anymore in the child support department. She says 8-year-old Knight has needs he didn't have 5 years ago when the order was put in place.

She says Nas is doing way better now than he was when the judge ordered him to cough up the $8k monthly support, so he's more than able to foot the bill for various expenses.

She's not specific as to how much more she wants, but whatever she gets, she wants add-ons to the base ... namely, 50% of school-related costs, 50% of any child care Kelis needs, and 50% of unreimbursed health care.

The judge has yet to rule.