I wouldn't advise utilizing nested IFs because they are tough to manage and I generally disagree with that approach on moral reasons. I would advise utilizing an INDEX(MATCH structure or a VLOOKUP.
We'll adapt your illustration of the laws slightly:
Min |  Class
--------------
0   |  Class A
2   |  Class B
5   |  Class C
8   |  Class D
11  |  Class E
14  |  Class F
Now, assuming your Max values are in sheet 2, column A, we'll use the following formula in the Class column of your output:
=VLOOKUP($A2,Sheet2!$A$1:$B$7,2,TRUE)