It is possible, but probably more difficult than with a USB 2 cable, which had only four conductors. USB C is a connector type for USB 3.1. A USB 3.1 data cable looks like this in cross-section:
Game console manufacturers have been known to do things like require their devices and peripherals to use chargers with data connections (this was the case with Sony PS3 peripherals). So severing the cable could possibly affect its continued compatibility with a Nintendo Switch, if this is a consideration, and you are unable to rule it out before cutting the cable.
Otherwise, if data connections in the charger are not present or not important, you just have to sever the cable and join the power/ground conductors across the in-line power switch (those marked with numbers 2 and 3 in the provided image). There are many more conductors within a USB 3.1 cable, so you just have to identify the right ones. The USB 3.1 data lines are co-axial, so there is little chance of rejoining them if you sever them. If you do not care about that, then it is fairly straightforward. It might be more economical to use a charger which allows detachable USB cables, if things go wrong.