Without a EIN or SS for spouse, it will have to be filed as Marred Filing as Single. Paper based, mailed to IRS.

I was advised to file as single by my tax guy. I'm bummed because I won't get tax credit for my kids (that live in Nepal) and wife. Also, my tax (owed) would've been 5k lower.

The reason he recommened you file is single is because they dont have SS to include them in your taxes... unless you can follow what max payne said.

You may apply as married with ITIN for your spouse/kids. I did it once 10 yrs back. you attach the ITIN with Tax documents and mail it to IRS.

https://www.irs.gov/individuals/individual-taxpayer-identification-number

What is an ITIN?
An Individual Taxpayer Identification Number (ITIN) is a tax processing number issued by the Internal Revenue Service. The IRS issues ITINs to individuals who are required to have a U.S. taxpayer identification number but who do not have, and are not eligible to obtain, a Social Security number (SSN) from the Social Security Administration (SSA).

What is an ITIN used for?
IRS issues ITINs to help individuals comply with the U.S. tax laws, and to provide a means to efficiently process and account for tax returns and payments for those not eligible for Social Security numbers. They are issued regardless of immigration status, because both resident and nonresident aliens may have a U.S. filing or reporting requirement under the Internal Revenue Code. ITINs do not serve any purpose other than federal tax reporting.

An ITIN does not:

Authorize work in the U.S.
Provide eligibility for Social Security benefits
Qualify a dependent for Earned Income Tax Credit Purposes
Do I need an ITIN?
Does the following apply to you?

You do not have an SSN and are not eligible to obtain one, and
You have a requirement to furnish a federal tax identification number or file a federal tax return, and
You are in one of the following categories:
Nonresident alien who is required to file a U.S. tax return
U.S. resident alien who is (based on days present in the United States) filing a U.S. tax return
Dependent or spouse of a U.S. citizen/resident alien
Dependent or spouse of a nonresident alien visa holder
Nonresident alien claiming a tax treaty benefit
Nonresident alien student, professor or researcher filing a U.S. tax return or claiming an exception

Agreed to tutepani.
Married taxpayer must file filing jointly no matter where is the souse living, will not bar to get ITIN.
For children born out side of US need to be in US and get SSN.

This is IRS recommendation ! As Tax Preparer, Strictly have to follow IRS guidelines.

IN GENERAL, WHEN A U.S. CITIZEN OR RESIDENT ALIEN IS MARRIED TO A NONRESIDENT ALIEN, THEIR FEDERAL TAX FILING STATUS IS MARRIED FILING SEPARATELY.

HOWEVER, YOU MAY CHOOSE ANOTHER FILING STATUS IF YOU QUALIFY.

IF YOU CHOOSE THE MARRIED FILING JOINTLY STATUS, BOTH SPOUSES MUST REPORT THEIR COMBINED WORLDWIDE INCOME.
BUT, IN GENERAL, REMEMBER…IF YOU DO NOT CHOOSE TO TREAT THE NONRESIDENT ALIEN SPOUSE AS A U.S. RESIDENT FOR TAX PURPOSES, AND YOU DO NOT QUALIFY FOR HEAD OF HOUSEHOLD FILING STATUS, THEN YOUR FILING STATUS WILL BE MARRIED FILING SEPARATELY.

THIS SUMMARIZES SOME OF THE OPTIONS AVAILABLE FOR TAXPAYERS WHO ARE MARRIED TO A NONRESIDENT ALIEN.

FOR INFORMATION ON ALL TYPES OF INTERNATIONAL TAXPAYERS, PLEASE VISIT IRS.GOV AND TYPE “INTERNATIONAL TAXPAYERS” IN THE SEARCH FIELD.

Source:https://www.irs.gov/newsroom/international-taxpayers-filing-status-if-married-to-a-nonresident-alien-youtube-video-text-skript

Regards,
A Square Accounting
https://asquareaccounting.com/
Email: asquare.acctservices@gmail.com
Phone: 406 345 5166