Unfortunately, there isn't any good rule as far as I know for whether "-se" after a vowel is pronounced as /z/ or /s/ ("-se" after a consonant is almost always /s/, with only a few exceptions like cleanse).
Nouns, verbs and adjectives spelled with "-se" may end in either /s/ or /z/.
Nouns with the "-Vse" spelling pattern seem to me to be almost evenly split: we have /s/ in base case chase lease release crease grease dose abuse excuse goose moose caboose mouse house grouse louse and vise (a US variant spelling of vice, in the sense "clamp") and /z/ in phase phrase praise raise tease ease disease nose rose prose hose pose fuse ruse muse bruise cruise rise guise disguise demise surprise pause cause clause applause noise poise. A few nouns can be pronounced with either /s/ or /z/: spouse, blouse, and vase.
There are more verbs ending in /z/ (like braise lose choose diffuse infuse peruse amuse devise advise revise comprise rise arise close transpose propose expose impose oppose please ease appease cause (a)rouse) than there are verbs ending in /s/ (chase debase encase/incase cease grouse) but either sound is possible. A few verbs can be pronounced with either /s/ or /z/: erase douse dowse.
For adjectives with the spelling "Vse", /z/ occurs in wise, but I think most others have /s/ (like loose close obtuse diffuse obese concise). I wasn't aware of this before Mitch left a comment, but apparently -ese adjectives (like Japanese, Portuguese) can be pronounced with either /s/ or /z/.