Chuck Liddell and his estranged wife Heidi just caught a break in their domestic violence case ... 'cause the L.A. District Attorney has decided NOT to prosecute the couple after they were allegedly involved in a physical confrontation last week.
TMZ Sports has learned the DA spoke with Liddell, Heidi, and their child ... and determined that they likely were involved in an argument that turned physical, but no one was seriously hurt -- so, no charges.
Chuck and Heidi's daughter did tell prosecutors she witnessed her parents pushing each other.