Did you confirm the date of purchase meets the requirements, which changed during 2023. Did you confirm this model does qualify, or does not qualify?

"she was told by Nissan that she could receive a credit of $7500"

Does anyone believe a dealership would not mislead the buyer to close a sale? Come on, raise your hand.

https://vpic.nhtsa.dot.gov/decoder/

Please check the link above to figure out if it is eligible to take credit.

New or used, before or after April 17, 2023?

https://www.irs.gov/credits-deductions/credits-for-new-clean-vehicles-purchased-in-2023-or-after

https://www.fueleconomy.gov/Feg/taxcenter.shtml

https://fueleconomy.gov/feg/tax2023.shtml

The dealer was required to give her a form/statement that tell her the amount of the tentative credit.

If the vehicle does qualify, are you typing the amount of the tentative credit (usually $7500) on the appropriate line?

The car is new, and it was purchased in June 2023. 

The dealer did provide a statement, I am not sure, what line should I be using for the credit? It is a personal use car and every line I try placing the credit on I get an error message.

The 8936-Schedule A, line 9.

Don't forget to check the box on line 1 and fill out part 1.

I put the credit on line 9 but it is not reflecting in the refund amount. 

Are you sure it qualifies?

"With the 2024 Leaf and its battery assembled in Smyrna, Tennessee it's now part of the new tax program that went into effect in April. The 2023 model does not qualify. Before the revamped program, the discount was based on EV sales numbers"

https://www.forbes.com/wheels/news/2024-nissan-leaf-ev-tax-credit/

Look at the 8936 (not the 8936 Schedule A).

Is $7500 showing up on line 9?

What is on line 10?