Mabaso spent last season on loan with Ajax Cape Town, where he failed to gather much-desired minutes under coach Stanely Menzo.
Since being promoted to the senior team at Chloorkop in 2012, the 26-year-old full-back has spent most of his time on loan spells, previously having had stints with Mpumalanga Black Aces and Maritzburg United.
Mabaso is now set to relocate to Port Elizabeth to team up with former Sundowns youth coach Dan Malesela, who is now in charge of the Chilli Boys.
"Both Sundowns and Chippa United are talking," says the source close to Chippa. "The deal is set to be concluded by this coming weekend."
Malesela has already welcomed a host of new players, including the likes of Brighton Mhlongo, Mark Mayambela and Kurt Lentjies, to bolster his team for the 2017/18 PSL season.