I remember shillings very well! In the good old days the British pound consisted of twenty shillings, and each shilling was divided into 12 pence! We had threepence and sixpence coins among others.
However, you'd get a better sense of Nathan's use of "shilling" if you look up the base verb form, "shill":
"to advertise or promote (a product) as or in the manner of a huckster; hustle"
Source: https://www.dictionary.com/browse/shill
The person who "shills" is a "shill" and Wikipedia has a page about shills: https://en.wikipedia.org/wiki/Shill
So it was originally a negative word, but I notice more and more it's being used in a more positive way these days.