Standard Basik phonology is:
Stops: p  b  t  d  k  g  ' /ʔ /
Fricatives: f  s  z  sh /ʃ/  h
Nasals: m  n  ng /ŋ/
Approx: w  l  j
Vowels: i  e  a  u  o

The Syllabic structure is (C(L))V + (C)
Where C is any consonant, and L is any consonant of higher sonority.
A word cannot begin with a Fricative or an Approximant, and ' can only appear between vowels.
The Sonority Heirarchy is:
[a e o i u] < [j w] < [l] < [m n ng] < [z] < [f s sh h] < [b d g] < [p t k ']
So, *snap would be allowed, but *nsap would not.