I earned non-resident income, but W2 only shows resident state

Unless you actually go to NY and work or have a business operating there, you probably don't need to file a NY return. Here are the rules from the instructions for Nonresidents of NY.

You must file Form IT-203 if you meet any of the following conditions:

• You have income from a New York State source (see Nonresidents: New York source income) and your New York adjusted gross income (Federal amount column) is more than your New York State standard deduction. Complete Form IT-203, lines 1 through 31 and compare the line 31 Federal amount to your standard deduction from the New York State standard deduction table.
• You want to claim a refund of any New York State, New York City, or Yonkers income taxes withheld from your pay or from your unemployment insurance benefit payments.
• You want to claim any of the New York State, New York City, or Yonkers refundable or carryover credits.