Villarreal appointed Pacheta as their new coach on Saturday after sacking Quique Setien earlier this week.
Villarreal lost three of their opening four games under former Barcelona coach Setien, and sit 15th in the table.
"In the afternoon (on Monday) Pacheta will take charge of his first training session," said Villarreal in a statement, confirming he would be officially presented beforehand.
Villarreal CF and @pacheta_oficial have reached an agreement for the manager from Burgos to be the Yellows' head coach for the rest of the 2023/24 season ??.
— Villarreal CF English (@VillarrealCFen) September 9, 2023
Pacheta was sacked by Real Valladolid in April during a relegation battle, with his former side eventually demoted from Spain's top flight on the final day of the season.
The 55-year-old had helped them reach LaLiga, as well as steering Elche from Spain's third tier into the top flight between 2018 and 2020.
Pacheta's first game in charge will be at home against Almeria on Sunday, 17 September.