Use of 100K ohm resistor along with 0.1uF capacitor?
The resistor is there to provide a DC path for the input bias current of the opamp.

It is normally selected to be the same as the DC resistance connected to the other input, so that the bias current does not produce a voltage offset at the output of the opamp. But in this case, the effective DC resistance on the inverting input is only 1k||100k = 990&Omega;, so that benefit is not realized here.

It is also selected to be high enough that it doesn't affect the frequency response of the circuit overall (in conjunction with the DC blocking capacitor). In this case, 0.1 &micro;F and 100 k&Omega; have a corner frequency of

$$\frac{1}{2\pi R C} = 15.9 Hz$$

This means that for frequencies above this value, the resistor will have no effect in the AC signal, but there will be a rolloff (loss of amplitude) below this frequency. This "loading" effect is probably what the author of the video was referring to.