Chris Tidland carded a matching 67 to join Stadler in the lead at 9-under-par 201 along with Kyle Thompson, who managed a 1-over 71 in the third round.
Stadler, who earned his first career victory on the Nationwide Tour last month at the Lake Erie Charity Classic, picked up a quick birdie at the opening hole, but found trouble later on the front nine with back-to-back bogeys starting at the par-4 seventh.
The 24-year-old persisted with a birdie at the par-4 ninth before making his move on the inward half.
Stadler birdied the par-3 11th to reach 7 under and ran home an 18-foot putt for a birdie at the very next hole. He then birdied the par-3 13th to make it three in a row en route to his share of first.
'I've felt really comfortable out here all week,' said Stadler. 'It's going to be a good day tomorrow.'
Tidland ran off three straight birdies starting at the par-3 third, but stumbled to a bogey at the eighth. The 31-year-old added a pair of birdies and a bogey on the back side in search of his first career victory on the Nationwide Tour.
'I played nice,' said Tidland. 'Made some really good putts.'
Thompson, who fired a 62 on Friday to take a three-shot lead after 36 holes, was on track early with back-to-back birdies from the fourth before a bogey at the ninth indicated troubles ahead.
Thompson double bogeyed the 14th and fell further with a bogey at the very next hole. He salvaged what he could with a birdie at the 16th to cling to a piece of the lead.
'Any time you can put yourself in this position, whether you play great on Saturday or you play poorly on Saturday, everybody wants to be right there for Sunday's round,' said Thompson, who is also seeking his first Nationwide Tour title.
Jason Caron held a share of the lead at one point, but bogeyed the 17th to fall back into fourth place along at 8-under-par 202 after a round of 67.
Mario Tiziani, John Elliott and Dave Christensen were two shots off the pace at 7-under-par 203. Keith Huber and Ryuji Imada followed at 6-under-par 204.