A couple of suggestions as I sew a lot of masks for a shelter. In addition to twill tape, another option for ties are long shoe laces. 42 inch or so. 15 pair for $12.00 from you know where. They are polyester not cotton so you do need to be a bit careful if you iron.
For nose piece, I use 1 strand of “telephone “ wire available from your hardware store. It’s plastic coated copper so it won’t tudt easy to fold also to tuck away sharp end.