A five-wicket haul from Greg Kerr and an unbeaten 40 from Doug Potter has fired Narromine into the Brewery Shield finals.
Narromine survived a scare from Nyngan to win Sunday's final round fixture by three wickets.
Keer bagged 5/25 from six overs as Nyngan was knocked over for 155 at Narromine's Dundas Oval.
Kerr destroyed the Brown Snakes' middle and lower order and only three of the visiting batsmen managed to make double figures.
Nyngan's total would have been even lower if it wasn't for the 29 sundries conceded.
Narromine didn't have it all their own way in the chase, losing seven wickets before they reached Nyngan's total.
The hosts lost 5/22 at one point in the middle order but key man Potter held firm.
His unbeaten knock guided Narromine to victory in the 27th over and secured a spot in the finals.
Cameron Bourke was the best of a beaten Nyngan side, top-scoring with 20 and bagging 4/24.
Narromine will now play Cobar in the semi-final with the winner of that match to take on minor premiers Dubbo.