Your electric guitar amp should be the last resort IMPO. Those amps for electro-magnetic pickups (e.g. pickups on the original Fender Stratocaster/Gibson Les Paul) have two major unfavorable characteristics; Uneven frequency response and distortion. Distortion can be avoided but frequency response could make it extremely difficult to adjust to your nylon string guitar.
I think an iRig Acoustic Stage system hooked up to a good flat sound system would be one of the best options.
I sometimes use an amp for flamenco and classical but oftentimes I only need to add just a little bit of db to the volume generated by the instrument itself. I am currently using the aux input (input for mp3 players) of a VOX Adio Air amplifier that has more or less even Freq. Res. than "Instrument" input, and free of any perceivable distortion (i.e. the amp sounds as "clean" as the guitar itself), with 50W output. And it is easy to carry around, with 2.9kg. It looks like a boombox from the 90s.
Given the experience with Adio Air, I have come to a new idea: if I need to add a little bit of volume, then I can possibly use one of those affordable bluetooth "go" speakers with an AUX input. The system could be somewhere around 15W, and larger speakers are desired but I have to try to figure out which sizes I can tolerate. In the least I can say now, VOX Adio has two 3" and I think it can very well be smaller.
FYR Back in time I recall Göran Söllscher was using one of these (↓ in the picture) for the same purpose, i.e. "to add some volume to that of the guitar itself".
I recall he was using a piezo transducer PU on a very specific point on the soundboard. The speaker enclosure (can I call it that way?) is the mandolin shaped wooden box that produces the sound very close to the sound inside (and not outside
) of his guitar, according to him. I am writing this remembering the article on a magazine I read when I was 16 or 17 so please search and verify the details on it.
Today we may have handier ways to achieve the similar result to this.
I hope this helps you.