The 41-year-old had been accused of a single count of stalking between January 2013 and August 2014.
Mr Nash, who also played for Stoke City and Preston North End, was found not guilty at Chester Crown Court after the prosecution offered no evidence.
It had been alleged that he accessed her emails and social media accounts and entered her house without consent.
Simon Parry, prosecuting, told the court the allegations were set amidst the "acrimonious break-up" of the marriage between Mr Nash and his ex-partner Jill.
Mr Nash smiled and nodded from the dock as his trial was aborted.
Mr Parry said the prosecution had just been provided with a "certain amount of material" by the defence which the prosecution "ought to be aware of".
Judge Nicholas Woodward directed a "not guilty" verdict be recorded and awarded legal costs to Mr Nash.
Lisa Judge, defending, told the court: "He has strenuously denied these allegations throughout."
Former Manchester City goalkeeper Carlo Nash has been cleared of stalking his ex-wife.