Nicholas Meregali was born on May 27, 1994, in Brazil. He began training Brazilian Jiu-Jitsu at age 16 at the ACJJ academy in Santo Antônio. His initial interest in the martial art was sparked by his younger brother, who frequently practiced newly learned techniques on Nicholas after returning home from training sessions. Under the mentorship of instructor Jeferson Adan, Meregali quickly demonstrated exceptional talent, securing numerous state-level victories and capturing a Brazilian National title as a blue belt.

Recognizing the need for a more competitive training environment, Meregali relocated to Porto Alegre in September 2013 to train full-time under renowned competitor and coach Mario Reis. This strategic move significantly elevated his skillset, rapidly establishing him as one of the world's premier colored-belt competitors. Dominating major tournaments at purple and brown belt levels, Meregali maintained a close relationship with his original instructor, Jeferson Adan, regularly returning to visit and train at his first academy.

In 2022, Meregali made a high-profile transition by moving to Austin, Texas, to train under legendary coach John Danaher at the New Wave Jiu-Jitsu team. Previously known primarily for his gi-focused competition style, Meregali quickly adapted to no-gi grappling under Danaher's analytical coaching approach. Training alongside elite athletes such as Gordon Ryan, Meregali credited Danaher with unlocking new dimensions in his grappling, significantly enhancing both his no-gi and gi skillsets.

Despite having no prior no-gi competition experience, Meregali delivered an impressive debut at the 2022 ADCC World Championships. He secured a bronze medal in the -99kg division and a silver medal in the absolute division, notably defeating 2019 ADCC champion Tye Ruotolo in the absolute semifinal. His remarkable performance at ADCC established him as a dual-threat competitor capable of excelling in both gi and no-gi formats.

Following his victory at the 2022 IBJJF World Championship, where he earned his third black belt world title and first absolute title, Meregali announced in 2023 that he would shift his competitive focus toward professional superfights. He quickly demonstrated dominance in this new format, submitting Pedro Marinho via mounted triangle in Who's Number One's first-ever gi match. He also secured an armbar victory over veteran competitor Roberto "Cyborg" Abreu at UFC Fight Pass Invitational 4 and choked out rival Kaynan Duarte in a no-gi match at WNO 19. Additionally, he captured the 2023 IBJJF Absolute Grand Prix, reaffirming his continued supremacy in IBJJF-style competitions whenever he chose to participate.

Entering the 2024 ADCC World Championships as a favorite in the -99kg division, Meregali experienced an unexpected setback. In a surprising quarterfinal match, he was repeatedly thrown by underdog Michael Pixley and ultimately submitted via D'arce choke. The final throw resulted in a severe shoulder injury, including a dislocation and extensive damage to both the anterior and posterior labrum, as well as multiple tendons. This injury required surgery and forced Meregali to withdraw from the ADCC absolute division, sidelining him from competition through early 2025 as he underwent rehabilitation.

Meregali is widely recognized for his aggressive, submission-focused style, finishing approximately 71% of his black belt matches by submission. His favored techniques include mounted triangles, armbars, and various chokes, reflecting his relentless pursuit of decisive victories rather than points-based outcomes. His tactical approach emphasizes positional dominance and constant pressure, consistently forcing opponents into defensive positions.

As a senior member of the New Wave team, Meregali has embraced a coaching role, assisting newer team members and refining techniques through Danaher's analytical methods. His influence extends beyond competition, as evidenced by his recognition as "Male Grappler of the Year (Gi)" by JitsMagazine in 2023, highlighting his unparalleled accomplishments in gi competition that year. Despite his injury setback, Meregali remains a significant figure in the BJJ community, poised to reclaim his status atop both gi and no-gi divisions upon his return.