3/32" is narrower than 1/8". The Shimano FC-M730-SG wants a 3/32" wide chain.
https://si.shimano.com/pdfs/si/SI-T-30A-000-00-ENG.pdf
That is an internal width which became common for bikes back in the era of that crankset, or just before. We normally talk external chain width for bike when we talk about sizing them. So don't get confused.
KMC and Shimano give the internal width of their chains. KMC sells seven speed and higher chains with 3/32 internal spacing too.
However the crank doesn't determine the specific chain you use as much as the specific rear cassette does. So if your bike is a mix and match set of components, you might need to share more info. But you probably are safe with a 7 or 8 speed chain that is also 3/32 width. (I think they all are, but maybe not)