In the 1910 Pottawatomie County census the name is misspelled as Grable.The census was taken April 1910.Nora is shown as the daughter of Bertie Grable, age 23, b. TX, parents b. TX, Bertie is widowed.
Below is a link to Pottawatomie County Vital Statistics which may prove helpful.Again, the name is misspelled Grable, although in a few of the records (divorce records) I found the name spelled Grabel.
You will find that Bertie Nichols married John H. Grable, 7 May 1904 in Pottawatomie County.
In looking at the 1900 Pottawatomie Co. census I found a John Grable, age 17, in the household of A. V. Grable.Nora's father is listed as having been born in MO.This John was shown as born in Kansas, but others in the family were b. in Mo, and the enumerator had started to write Missouri for his birth. I think this is a good possibility.
The only Bertie Nichols that I could find in 1900 Pottawatomie was born in 1899, not the right one.
But this does give you the mother of Nora Bell Grabel.