The F means Farads which is the unit that tells you how big the capacitor is. nF is a unit of Farads just like mF or uF, where the prefixes mean:
n = nano (10^-9, one billionth)
u = micro (10^-6, one millionth)
m = milli (10^-3, one thousandth)
k = kilo (10^3, one thousand)
M = mega (10^6, one million)
G = giga (10^9, one billion)
They just describe the different orders of magnitude just like {byte, kilobyte, megabyte, gigabyte} or {mm, meter, cm, km}. So, no they are not the same. They are different by multiples of a thousand times.
So 10nF = 10x10^-9 Farads = 10,000pF = 0.01uF
Where is the pot supposed to go in the circuit? Either way, 100K is a very large resistance. Not many things need a resistance larger than that. When you meant small, did you mean you thought the max resistance was too low? or that the pot itself was too small? The size of the pot (or any resistor) does not dictate it's resistance as much as it dictates how much current the pot can handle running through it. It should be fine for your application. You should try to find how much current will be flowing across the pot at the resistances you are planning to use it at and multiply the pot's resistance by the square of the current:
Power = (Current^2)(Resistance)
If at any time the power exceeds 0.1W, then you need a bigger resistor, since that is the maximum power specified by the pot you showed me.
But the real question now, is will you use the new powers granted by your invention for good?...or for evil?