It's not clear why you'd want "NAYS:" or "nay" rather than "NAYS:" or "nays:". Try:
1. Mark the whole document as hidden text.
2. Use a wildcard Find/Replace where:
Find = [Nn][Aa][Yy]*^13
Replace = ^&
and the replacement font is set to not hidden.
3. Use an ordinary Find/Replace to Find all hidden text and replace it with nothing.
Note that this Find all lines with "NAY" or "nay"; it's not limited to lines with "NAYS:" or "nay".

Alternatively, if it really must be "NAYS:" or "nay", try:
1. Mark the whole document as hidden text.
2. Use a wildcard Find/Replace where:
Find = NAYS:*^13
Replace = ^&
and the replacement font is set to not hidden.
3. Use a wildcard Find/Replace where:
Find = nay*^13
Replace = ^&
and the replacement font is set to not hidden.
4. Use an ordinary Find/Replace to Find all hidden text and replace it with nothing.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]