Our sources tell us Cardi's second collection with Fashion Nova is already vastly outperforming her first collab with the fast-fashion giant, a pretty tall order considering her first venture sold out within minutes.

We're told Fashion Nova prepared for "Season 2" of Cardi's spring-summer line collection by having nearly 5 times the amount of inventory as the first go-round ... and they're still struggling to meet the demand, with the vast majority of styles selling like hotcakes.

The numbers are impressive, but here's something else to give you a sense of just how wildly successful Cardi the businesswoman is ... Nasdaq is congratulating her with a massive billboard in Times Square!!! Now that's clout.

As we reported ... Cardi rolled out her new line as only she could, by shaking her ass and rapping during a launch party at the Hollywood Palladium. Tons of celebs showed up to support Cardi, including Master P, YG, Romeo, Lamar Odom, Nikki Bella, Swaggy P and Jeremy Meeks.

If you didn't get your hands on some Cardi B fashion merch, don't give up hope yet ... we're told Fashion Nova is planning weekly drops for each style to give everyone a chance to snag her new designs.

Just be sure to keep your finger on the trigger, or you might miss out. Okurrr!!!