Dreamings only:

Consider possibility of options that insulate wire electrically (just)
& place a thermally insulating layer outside the NiCr so preferred
heat paths are inwards.

IF you can control max temp rise well then various thermally
conductive coatings may work. (eg thermally conductive epoxies -
probably loaed with metal powders -=3D electrical conductivity may be
good or poor depending on loading.
--=20
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