Nieto was born in Villa del Río, Córdoba, Andalusia, and joined Real Betis' youth setup in 2014, from Séneca CF.
[2] Nieto scored his first senior goal on 2 October 2016, netting the fifth of a 5–0 home routing of CD San Roque de Lepe in the Tercera División.
[4] Upon returning, Nieto started to feature more regularly for the B-side before signing a two-year contract with Cádiz CF on 30 August 2019; he was assigned to the B-team in the third tier.
[6] Nieto made his first team – and La Liga – debut on 23 January 2021, coming on as a late substitute for Anthony Lozano in a 0–3 loss at Sevilla FC.
[10] A regular starter for the Valencians, Nieto scored ten goals during the campaign (four only in the promotion play-offs) as Eldense returned to Segunda División after 59 years.