[1] He made his professional debut in 2017 with the rookie–level Gulf Coast League Mets, posting a 5.24 ERA across 19 games (8 starts).

[2] In 2019, Núñez split the year between the Single–A Columbia Fireflies and High–A St. Lucie Mets, accumulating a 5–4 win–loss record with a 4.39 earned run average and 94 strikeouts in 80 innings pitched.

[8] On March 18, Núñez was placed on the 60-day injured list after undergoing Tommy John surgery, causing him to miss the entirety of the season.

[14] Núñez debuted against the Atlanta Braves that same day, pitching two innings in relief of Adrian Houser, and yielding one run.

On September 13, it was announced that Núñez would miss the remainder of the season with a flexor injury; he subsequently received a platelet-rich plasma injection in an attempt to avoid surgery.