Nottus plays traditional heavy metal with all lyrics written in Portuguese, grounding the band firmly in a local identity unusual for the genre. Vocalist and main composer Cristiano Mendes steers the songwriting toward historical and religious subjects — the 2014 EP A Marcha Negra includes the track A Lança de Longino, which draws on the legend of the spear said to have pierced Christ at the crucifixion.

NouseyesuoN fuses heavy metal with orchestral classical arrangements, structuring their 2020 album Death Is Nothing To Us as a suite of nine movements — each track numbered as an Opus — covering ground from Epicurean philosophy to Mayan mythology and medieval death imagery. The band's lyrical scope is unusually literary, drawing on poetry, nihilism, and esoteric history to give the music an almost academic density.

Nova Darkness is a Chilean melodic death metal band that released their debut album Of Doom and Grief in November 2019, a ten-track record incorporating neo-classical and symphonic elements alongside death metal riffing. The band followed it with Nigredo Tenebrae in January 2024, continuing to develop a sound influenced by the melodic death metal tradition of the 1990s.

NoWrong deliver punishing thrash metal with a blunt fixation on politics, social inequality, and modern urban violence, channeling those themes across the 13 tracks of their 2014 debut Prognostic of a Great Disaster. The record leans heavily on classic Bay Area and Teutonic influences, keeping the riffs fast and the production raw without losing coherence.

Nox is a black metal band from Valparaíso, Chile, formed in 2008, operating in the tradition of raw, underground South American black metal. The band has released material independently, exploring themes of darkness and occultism through a stripped-back, atmospheric approach to the genre. Nox represents part of a broader resurgence of extreme black metal activity within the Chilean underground scene in the 2010s.

Nox Eterna have been refining their brand of classic heavy metal since the mid-1990s, with a sound that balances crunching riffs against melodic, hard-rock-tinged choruses built for the stage. Their catalog spans multiple decades and includes the albums Mind Abduction (2009) and The Ocean Is Mine (2014), and in 2007 the band was selected among the top fifty acts from a national pool of 300 to represent Brazil at Wacken Open Air.

NoxEternum is a black/death metal band from Alto Paraná, Paraguay, active from 2022 until their split-up. In their brief existence they were prolific, releasing two full-length albums — "Portal to NoxEternum" and "The Black Window of the Mind" — along with two singles, all in 2022.

Nucflash is a thrash metal band from Buenos Aires, Argentina, that emerged from an earlier project called Warfare before settling on their current lineup and name. They released the EP Spreading the Virus in 2011 and The Purifying Fire in 2017, and shared the stage with German thrash veterans Kreator in 2013.

Nucleador came out of Sergipe playing uncompromising crossover thrash in the mold of the 1980s hardcore and thrash collision, recording their first EP within six months of forming despite none of the members having prior experience in the genre. They've built a steady catalog since, including the 2014 EP United by the Toxic and the 2021 full-length Back From the Dead, earning a spot at São Paulo's Night of Living Thrashers festival early in their career.