Her employer will also need to obtain an approved LMIA before she can apply for a work permit. That's a 4-6 month process that requires the employer to advertise the job for a month first to prove no Canadian could be found for the role. Once/if the LMIA is approved, she can actually obtain the work permit at the border (she doesn't have to apply for one online/via paper and wait). The LMIA part is however the difficult bit. Most employers aren't willing to go through the process and if there are enough nursing assistants in Canada, it won't be approved.