I need to file for nonemployee compensation, which should be a 1098-NEC, but employer sent a traditional 1099-MISC

You will need to contact the issuer. If you should have received Form 1099-NEC, they need to issue you a corrected Form 1099-MISC with no income as well as Form 1099-NEC with the correct income. 

From IRS Instructions for Forms 1099-MISC and 1099-NEC (2020)

Specific Instructions for Form 1099-NEC

File Form 1099-NEC, Nonemployee Compensation (NEC), for each person in the course of your business to whom you have paid the following during the year:

• At least $600 in:

1. Services performed by someone who is not your employee (including parts and materials) (box 1);

2. Cash payments for fish (or other aquatic life) you purchase from anyone engaged in the trade or business of catching fish (box 1); or

3. Payments to an attorney (box 1). (See Payments to attorneys, later.)
    

Specific Instructions for Form 1099-MISC

File Form 1099-MISC, Miscellaneous Income, for each person in the course of your business to whom you have paid the following during the year:

• At least $10 in royalties (see the instructions for box 2) or broker payments in lieu of dividends or tax-exempt interest (see the instructions for box 8).

• At least $600 in:

  1. Rents (box 1);

  2. Prizes and awards (box 3);

  3. Other income payments (box 3);

  4. Generally, the cash paid from a notional principal contract to an individual, partnership, or estate (box 3);

  5. Any fishing boat proceeds (box 5);

  6. Medical and health care payments (box 6);

  7. Crop insurance proceeds (box 9);

  8. Payments to an attorney (box 10) (see Payments to attorneys, later);

  9. Section 409A deferrals (box 12); or

  10. Nonqualified deferred compensation (box 14).