Nesting AND NOT ISBLANK with MULTIPLE IFs

I can't find an example close enough to this one on Stackoverflow so here goes :

I want to return a message "Type?" if cell X is blank and cell Y has any text. But i'm trying to nestle it into an existing set of IFs.

Existing : =IF($G241="Evo";M241*L241;IF($G241="Free";M241*L241;IF($G241="GN";M241*L241))))

Nestling this into the above : =IF(AND(NOT(ISBLANK($J234));ISBLANK(G234));"Type?";"OK")

I tried this but it returns FALSE, maybe due to the AND i'm using, which I need since i'm creating a return based on two cells two cells.

=IF($G240="Evo";M240*L240;IF(AND(NOT(ISBLANK($J240));ISBLANK(G240);"Type?";"OK");IF($G240="Free";M240*L240;IF($G240="GN";M240*L240))))

getting : Error AND expects boolean values. But 'Type?' is a text and cannot be coerced to a boolean.