On August 23, 2010, about 0945 Pacific daylight time, a Cessna U206C, N29100, nosed over during landing at Idaho County Airport, Grangeville, Idaho. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 91 as a positioning flight. The commercial pilot was not injured; the airplane sustained substantial damage to the fuselage, wings, and empennage. The airplane departed Concord airstrip (25 miles southeast of Idaho County Airport) at 0930, en route to Grangeville. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that he began the day at Grangeville at 0615, for a 14 CFR Part 135 flight to Campbell’s Ferry on the Main Salmon River. After landing and unloading his passenger, he departed for the airstrip at Concord. The pilot stated that during the landing he noticed that the airplane was rattling and shaking, but he had no problem maintaining a straight line on roll out. He taxied back to the tie down area, and parked the airplane. The pilot inspected the landing gear and observed the nose gear scissor lying on the tire; the upper end had snapped off (separated from the casting). He walked out to where he touched down, and observed good tracks on the grass in the morning dew. He saw that the nose wheel track first appeared after a large ground squirrel hole. The pilot reported that earlier in the summer he had filled in some of the holes. The pilot contacted his mechanic, who informed him that he should be able to fly home if he tied the nose gear scissor up. After doing that, the pilot taxied about 1,000 feet on the runway, and made two 180-degree turns with no problems encountered. The pilot then departed for Grangeville. During the landing, the pilot held the nose off for about 1,500 feet, and then eased the nose down. The airplane made a hard left turn that he could not stop with right rudder and brake. When the airplane reached the edge of the runway, it nosed over. The pilot indicated that the nose wheel had evidently cocked 90 degrees prior to the landing.