McKibbin bagged the third position in the reality singing competition behind Justin Guarini and Kelly Clarkson. According to the reports, she was later in the hospital on life support.
McKibbin was taken to the operating room where her organs were harvesting room and was pronounced dead around 3 a.m.
The report further suggests McKibbin is best remembered for performances like Alannah Myles' song, "Black Velvet." Nikki also covered Alanis Morissette, Stevie Nicks, Melissa Etheridge, and Janis Joplin.
TMZ also stressed Nikki's 15 years old son, Tristan Langley, auditioned for American Idol in 2014, and made it to Hollywood, but could not go to further rounds.
Following Nikki's death, many fans and friends took to their social media to pay their tribute to the singer. One wrote,
"I witnessed my friend Nikki (McKibbin) Sadler go from a Karaoke bar to finalist on 1st year of American Idol. She is on life support after suffering an aneurysm. They will end life support tonight. Please pray for her husband Craig and family. I am heartbroken.❤🙏❤🙏."
Another one wrote,
"I've known Nikki McKibbin for over 20 years. Before she appeared on the first American Idol. She suffered a fatal aneurysm on Wednesday. She will be missed. She never let fame go to her head. Rest in peace, my friend."