Page 306 - Makino,Tsutusi.DictionaryOfIntermediateJGrammar

232 nashi de wa / -neba naranai
The only difference between the two versions is that - nashi de wa ver-
sion sounds slightly more formal probably due to the archaic form
nashi.

However, - ga (i)-nakereba cannot be rephrased by - nashi de wa when
the sentence is a question, request, command, suggestion, or volitional
sentence. Examples follow.
<
[41 {ttz+m~fhl~/*tm&~~u~ I@L~SW/RLT IZS
b>/t%LI:br5T$7P/t%L3 LL ?lo
(If you don't have a job, look for one / please look for one / why
don't you look for one / let's look for one.)
E XL 4L*i5
[5] I%&#L\&Cf hlB/*%!k& LTlbl $%T% %La Sbl,
(If there isn't a teacher, study by yourself.)

[6] {~&hfQkthC%/*~&<ttl, r? LI:bblbrT.f$,
(If I don't have money, what shall I do?)

-neba naranai taiga 5 ph,: <w>

must; have to; should
[REL. -nakereba naranai]