Selected by the Rams in the fifth round of the 2023 NFL draft, Nacua set rookie records for receiving yards and receptions, along with being named to the Pro Bowl and as a second-team All-Pro.

[19] In his first professional football game, Nacua caught three passes for 32 yards including an 11-yard touchdown reception in a 34-17 preseason loss to the Los Angeles Chargers.

The Seahawks were heavy favorites because the Rams were coming off of an injury-riddled 2022 season and the team was without star receiver Cooper Kupp, who had been sidelined with a hamstring injury.

[20][21] Though he was first questionable with a rib injury, in his second game, Nacua broke the NFL single-game record for catches by a rookie as he caught 15 passes for 147 yards in a 30–23 loss to the San Francisco 49ers.

[28][29] Against the New York Giants in Week 17, Nacua caught five passes for 118 yards, including a season-long 80-yard catch-and-run to set up a touchdown in the Rams' 26–25 victory.

[34] In his first career playoff game, Nacua caught nine passes for 181 yards including a 50-yard touchdown in the Rams' 24–23 loss to the Detroit Lions in the NFC Wild Card Round.

[41] After missing five games, Nacua was activated off injured reserve on October 24 and played in the Rams' Week 8 matchup against the Minnesota Vikings, finishing with 106 receiving yards in a 30–20 victory.

[42] A week later, Nacua caught one pass for 11 yards at Seattle, but was ejected from the game in the second quarter for unsportsmanlike conduct after throwing a punch during a post-play altercation with Seahawks Linebacker Tyrel Dodson.

[44] Four days later in a Week 15 Thursday Night Football matchup against the San Francisco 49ers, Nacua caught seven passes for 97 yards in a touchdown-free, rain-filled 12-6 victory at Levi's Stadium.

[51] On April 25, 2024, Nacua signed a multi-year footwear and apparel deal with Jordan Brand along with Raiders defensive end Maxx Crosby.

[52] On September 4, Nacua signed an endorsement deal with Gatorade, along with Ravens quarterback Lamar Jackson, Vikings wide receiver Justin Jefferson, and flag football player Diana Flores.