The Uruguayan was heavily linked with the Forest job.
The former Brighton and Sunderland boss was heavily linked with the job after leaving Greek side AEK Athens.
However, earlier this week he agreed on a deal to become the Real Betis manager. Poyet, who played in La Liga for Real Zaragoza, is taking up his first coaching position in Spain and will be hoping for success at the Benito Villamarin.
The Nottingham Post reported this week that Forest were now looking at new potential candidates, confirming that talks had been ongoing with Poyet for the Forest job and that they had been essentially snubbed for Betis.
Now Poyet has been speaking about his decision to head to the Verdiblancos. He is quoted by Football Espana as stating:
“When they called me about the Betis job it was a simple decision.
“It’s a pleasure to be here and I’ll give my all for this club. From here on in I will prove myself with hard work and results, not words.”
The current names being linked with the Forest job now range from Leeds head coach Steve Evans and Republic of Ireland boss Martin O’Neill to the likes of Nigel Pearson and Ivan Vukomanovic.