Also note that in the regex set expression  [\w+\d+\/] the \d component is redundant because \w includes \d (the digits
[0-9]). Furthermore, the expression  [\w+\d+\/] contains the character '+' twice, a redundancy that may lead the casual reader to think this character is a quantifier associated with the \w or \d subsets. (Also, the '/' in this set does not have to be escaped.)

So...

perl -wMstrict -e
"my $NetPattern = 'mbist [\w/+]* \[ \d+ \]';
 my $NetName = 'top_level/mbist_wrapper_pix2d[22]';
 if ($NetName =~ qr/$NetPattern/x) {
  print 'match'
  }
"
match
[download]

Or perhaps better yet...

perl -wMstrict -e
"my $NetPattern = qr{mbist [\w/+]* \[ \d+ \]}xms;
 my $NetName = 'top_level/mbist_wrapper_pix2d[22]';
 if ($NetName =~ $NetPattern) {
 print 'match'
 }
"
match
[download]