There is nothing like an "nCr button" on Casio fx-9860G, sorry. In any case, I have already found the answer, thank you.
For posterity:
To calculate binomial coefficients, you need to find the "C" function (the fat-looking C letter) under the CATALOG in the C's and type the n and r values on either side of the C as it appears on screen (e.g. 4C2).
To calculate binomial distribution, 1) go to "Menu", 2) select "STAT", 3) select "DIST" (under F5), 4) select "BINM" (under F5), 5) select "Bpd", 6) change inputting the DATA from "List" to "Variable" (F2), 7) enter your data and 8) select "Execute."