Before she can sit for the NCLEX, she has to pick a state to apply for licensure. I would assume it would be where you live. The information for foreign nurses will be listed on the web site. Each state is a bit different, but usually the board has a process to review the nursing program and verify the education. This site has lots of information for each states , so you can read it. Once the board approves her application she will get approval to sit for the exam in the Philippines.
Getting a job is the USA is a challenge due to the economy. Being an ER Nurse is great specialization, I would suggest she get as much paid experience she can ( over 2 years or more) and take a exam Certified Emergency Room Nurse. It use to be hospitals would sponsor nurses, paying there moving costs and provide housing. This was done in the day nurses were getting signing bonuses. Now it s difficult to find a hospital to sponsor a foreign nurse, this is because they are still waiting for nurses they signed contracts in 2005. To sponsor a nurse, the hospital has to show that there are no Nurses who have legal status available to work these positions. Considering how health care is changing, many hospitals closing, merging, and changing management it is hard to find a hospital that hasn't had any of the above changes. What I am referring to here is Green Card and permanent residency.
Experienced nurses who can find positons that require a BSN and special nursing skills can file for H1B position. These positions are also hard to find due to the economy. If your sister is an expert ER nurse with national certifications and can find a place that needs a BSN only position with no legal nurses who qualify she may get this visa, which is not a permanent visa but a working visa.
You could also petition your sister for a F4 Visa if you are a citiizen
. It may be a long wait but a good back up plan for the employment route.