The 20-year-old from Tunbridge Wells impressed in three outings in his InterCleanse-backed car during the 2018 season.
InterCleanse will be backing him again at Croft along with Shoreham Vehicle Auctions and Singleton Dental Implants.
Edwards commented: “It would have been great to do the first event at my home circuit of Brands Hatch, but Croft was always the realistic target with the budget we have.
“I’m very happy that I’ll be with MRM – their drivers Jack Young and Brett Lidsey are 1-2 in the championship and they also lead the teams’ standings so I know I’m in excellent hands when it comes to car set-up and engineering.”
He added: “The plan is to be on the grid a few more times after Croft as well. It might be the final year for the UK Clio Cup but still nothing comes close for drivers looking to gain credibility in front of the touring car teams and potential sponsors and I want to take every opportunity I get to do the best I can.”
MRM Team Principal Mike Ritchie said: “Nathan is a very exciting talent and we’re delighted to be running him alongside Jack and Brett at Croft.
“We were fortunate to achieve a pair of 1-2 results at Donington Park last time out so the next thing would be an even rarer 1-2-3 – Nathan knows how tough this grid is but he’s certainly got the ability to help give us a chance of a result like that…”