The best replacement for nylon strings is steel strings.

The best alternatives to nylon strings are rated as following:
★★★★★  steel strings
★★  steel
★  metal strings
  steel ukulele
  steel guitar

Your alternative for nylon strings is not listed? Suggest!
Speaking about nylon strings, one probably shouldn't forget about pick.

Other search terms related to nylon strings and their ratings are:
★★★★★ pick
★ steel strings
You have in mind a companion for nylon strings and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of nylon strings in all years. Click on graph for more.
nylon strings
steel strings
steel