This should do the trick:

my $templateformat = 'w<NM>b<NM>cm<CH>sw<SW>';
my $inputexample = 'w8b8cm512swno';

my @splittemplate = split /[^A-Z]+/,$templateformat;
[download]

my @splitinput = split /\D+/,$inputexample;

my @splitinput = split /[^(\d)(no)]+/,$inputexample;
[download]

Update:
Include "no" as an element of the second array.