I see LRASM and NSM in different roles. LRASM is the ideal missile to be cued with far off assets at large high value, well hardened or protected targets. Its a 2 ton missile (three times the mass of harpoon), and won't be replacing harpoon box launchers, so it will have to most likely exist in the VLS tubes, competing with air defence missiles for space. Or on a platform like the ANZAC's, never abled to be fitted. Even if they did fit, what is going to cue them. But ideal for fighters, P8's, DDG's.
NSM on the other hand is usefully longer ranged than harpoon, a whole lot more likely to be able to make it to the target. It can easily replace boxed harpoon launchers as its designed (and weight 2/3rds that of a Harpoon, or 1/5th that of a LRASM), providing additional shots in the process. It could be easily fitted to the Anzacs and smaller ships and give a useful upgrade. Given it seems we will have the Anzacs for while yet, even small buy of NSM box launchers would go a long way.