Williams who found himself on the wing as a replacement against Edinburgh last Saturday, takes the place of Cathal Sheridan, while Holland returns to the side after recovering from a groin injury with Rory Scannell moving to the bench.
The front row changes include hooker Duncan Casey coming straight in to the squad and tighthead prop John Ryan starting ahead of Paddy Ryan this week.
Fittingly, Billy Holland will captain the province after previously leading the Munster 'A' side out at Meadow Lane in January 2011, when they narrowly defeated the home side by a point.
"It is tough going to Nottingham and playing them at their home ground. They are a physical team and we've to match that physicality away from home," he said.
"Last weekend's scoreline against Plymouth doesn't reflect the quality that was played and we need to be wary as we are expecting a backlash, and a side always wants to perform in front of their home support."
MUNSTER 'A' (v Nottingham County): Ronan O'Mahony; Andrew Conway, Ivan Dineen, Cian Bohane, Darren Sweetnam; Johnny Holland, Duncan Williams; Alan Cotter, Duncan Casey, John Ryan, Billy Holland (capt), David Foley, David O'Callaghan, Sean Dougall, Shane Buckley.
Replacements: Niall Scannell, Paddy Ryan, Darren O'Shea, Barry O'Mahony, Brian Haugh, Rory Scannell, Niall Kenneally.