Which of Garmin's many standard Nuvi devices do you have in mind?
Do you intend to delete the existing (presumably) full set of maps from the device's internal memory before you start, thereby creating space to (hopefully) allow you to fill it with a new more up to date full map set?
Why do you mention a SIM card, as used in a mobile phone?
Why are you adverse to inserting a good quality SD card into your standard Garmin Nuvi device and loading the unlimited * new lifetime of updated maps to the SD card, like any standard person?
* Few things in life are ever unlimited