Don Mancini (the creator of the characters and series) is not involved in this film, and has, along with Alex Vincent, Christine Elise, and Jennifer Tilly, expressed his lack of interest in it.
The original creators of Chucky (and every sequel before this) decided to do a separate television series to continue the storyline there.
Mark Hamill previously voiced Chucky in the television series Robot Chicken (2001). The episode: Plastic Buffet (2005).
Tom Holland, the director of the original film, posted on Twitter about Mark Hamill's casting of Chucky as a "smart move."
The horror film the kids are watching with Chucky interpreting it is [The Texas Chainsaw Massacre 2 (1986)].