If you have a instrument rating and wish to use it for NVFR you must meet the following requirements.
For private & aeriel work you must meet the aeronautical and recency requirements for night VFR. CAO 40.2.2 Appendix 1
For Charter you must have 10 hrs x/country flight time using NVFR, including 2 nav's of at least 300 nm or 3 hrs duration. Must also meet recency requirements.
To me sounds easier to just do the night VFR endorsment as you will still need 10hrs night and you'll have an extra endorsment for minimal extra cost (cost of flight test). When just starting out you will be likely operating VFR for a year or 2 and might not be able to afford to keep renewing your instrument rating if you are not using it. At least you can still operate under NVFR.