To get a U.S. Green Card under the EB2 National Interest Waiver category, there are two independent steps. The first step is to file USCIS Form I-140 petition to verify that your employment in the United States has enough national interest to waive the otherwise required Labor Certification (or PERM Labor Certification). 

After your EB2 NIW based Form I-140 is approved, you may file USCIS From I-485 to receive your Green Card. Many people prefer EB2 National Interest Waiver application over the EB2 based PERM Labor Certification for several reasons. 

• First, you can self-petition the EB2 NIW. This means that you can file for your Green Card application by yourself, without the consent or knowledge of your employer, or your employer's sponsorship. 

• Second, the regulation requirements for EB2 National Interest Waiver are easier than that for EB1 Alien of Extraordinary Ability (EB-1A). 

• Third, with EB2 National Interest Waiver, you can skip the Labor Certification process. Filing a Labor Certification could be a burdensome and time consuming process.