The Meriden born midfielder had two spells at the club last season on loan from Coventry City.
The Sky Blues, were the club which Walker joined aged eight and he progressed all the way through to City's first team making his debut on December 28th 2008.
He made another substitute appearance that season and played the whole game against Hartlepool United in the League Cup last August.
Nuneaton Boss Kevin Wilkin told his club's website: "I am convinced that Adam will have a huge impact on the team and the league. We all saw in his first spell just how good he was and over the next few moths, we will be working to bring that out again. This time lst year, he was in Coventry City's squad facing us at Liberty Way and you don't get into a Championship squad without quality."