VanZant first hinted at the date months ago.
The UFC Fight Night event, which will take place at Barclays Center and air on ESPN+, will mark the first event of the UFC's five-year deal with ESPN. The $1.5 billion deal made ESPN the UFC's exclusive domestic broadcast partner of non-pay-per-view events.
VanZant (7-4) will be making her first appearance since a January loss to Jessica-Rose Clark. VanZant, 24, broke her arm during a decision loss to Clark and has spent the rest of the year returning to health.
Fighting out of Portland, Oregon, VanZant is 1-3 in her last four contests. She began her UFC career with three consecutive wins. One of her losses came against current flyweight champion Rose Namajunas.
Ostovich (4-4) will be making her third appearance in the UFC. She was a contestant on The Ultimate Fighter reality series last year and has gone 1-1 thus far in the Octagon. She fights out of Waianae, Hawaii.
The UFC has not yet announced a main event for the card.