After graduating, Hatten started his career as an intern and then writing assistant at Team Downey. While there, he wrote his first spec script titled Maximum King!, which focuses on Stephen King during production on his only directorial feature film, Maximum Overdrive. The script was later voted onto the 2016 Black List. He went on to write another script on spec titled Ballerina, which was purchased by Lionsgate in 2017 to be produced by John Wick production company Thunder Road Films. Hatten credited the tone of Ballerina with what led to him being brought onto the John Wick: Chapter 3 – Parabellum writing team and later John Wick: Chapter 4.
Hatten also wrote a number of scripts that Zack Snyder would produce starting with the 2021 Netflix films Army of the Dead and its prequel Army of Thieves, followed by the epic space opera Rebel Moon.
For television, he wrote pilot episodes for (Future) Cult Classic, a satirical television series, and I Know What You Did Last Summer, which he also received executive producer credit for.