He was picked by the Houston Astros in the fifth round of the 2014 MLB draft out of Los Alamitos High School. They agreed on an above slot signing bonus, which the Astros were unable to pay when first round pick Brady Aiken refused to sign, which lowered their bonus pool. He went unsigned himself, and attended the IMG Academy, and was then drafted by the Padres in the third round of the 2015 MLB draft.
Nix grew up playing youth baseball as a catcher. He was involved in a home plate collision at the age of 11 that led to chronic pain in his back, and required spinal fusion surgery, which he had at the age of 12.[1] He grew up a Cardinals fan.[2]
The Houston Astros selected Nix in the fifth round, with the 136th overall selection, of the 2014 Major League Baseball (MLB) draft. Nix and the Astros agreed to terms on a contract, including a $1.5 million signing bonus, well above the $370,500 recommended at the 136th slot.[6] However, the Astros failed to come to terms with Brady Aiken, the first overall selection of the draft, which reduced their allotted draft pool, leaving them unable to sign Nix without incurring penalties. The Astros reneged on their agreements with Nix and Mac Marshall,[8] and offered Nix a $616,165 signing bonus, which was the most the Astros could offer him without incurring penalties. Nix rejected the offer.[3][9] He filed a grievance against the Astros,[10] which put his collegiate eligibility in jeopardy.[3] The two sides reached a settlement in December, but did not disclose the terms.[11]
Rather than wait for a ruling on his collegiate eligibility, Nix opted to take a post-graduate year at the IMG AcademyinBradenton, Florida, to play for their baseball team.[12] In this way, he became eligible for the 2015 MLB draft.[13] After watching him throw for scouts, Keith Law, a draft expert for ESPN, wrote that he believes Nix could be a first-round pick.[14] In ten starts for the IMG Academy, Nix improved his fastball velocity to 95 to 97 miles per hour (153 to 156 km/h), improved his changeup, and developed a curveball.[9]
Nix did not consent to being reselected by the Astros in the 2015 draft.[3] The San Diego Padres selected Nix in the third round, with the 86th overall selection, of the draft.[15] He signed with the Padres, receiving a $900,000 signing bonus.[16] Nix was assigned to the AZL Padres, where he spent the whole season, pitching to a 0–2 record with a 5.49 ERA in seven games. In 2016, Nix pitched for the Fort Wayne TinCaps of the Class AMidwest League,[17] where he posted a 3–7 record with a 3.93 ERA.[18]
In 2021, Nix suffered an elbow injury in Spring Training that required Tommy John surgery.[27][28] He underwent the surgery in mid-March. He elected free agency on November 10, 2022.
On October 6, 2019, Nix was arrested and charged with criminal trespassing, having allegedly broken into a house in Peoria, Arizona, through a doggy door. An inebriated Nix was kicked in the face and tased by the homeowner prior to Nix fleeing, and was arrested by local police not far from the scene.[30]