Yeah, those cans are best for touchup. You'll probably be underwhelmed by the results.
Two other options though:
First is buy a used bumper painted with the correct color code, probably tougher to find in good condition but you could watch for one. I did this for my daughter's silver Sentra. You can't tell it's not original.
Second is to buy one already painted from a place like in the link below. Did this on my son's Altima which was also silver and it matched pretty well. We had to nip and tuck in places for it to fit well but it did the job.
Lastly, no I'm not a silver Nissan lover they were just cheap cars needing some work that I got for my kids.
NEW Painted To Match Front Bumper Cover Replacement for 2003-2005 Toyota 4Runner | eBay