Perception is:

Grass always looks greener on the other side of the fence.  Is it really green?  You have to go over the fence to find out.  You might be disappointed.  You might be happy.

While living abroad:

You will miss Nepali festivals, friends and family, food
You will miss hariyo dada kaada khola naala
You will miss hustle and bustle of the place you grew up

While living in Nepal:

You will miss cleanliness, ease of doing business and organization of the first world
You will miss on-demand hot water, electricity, clean air, good medical care, arts and entertainment
You will miss having an insulated home and driving nice automobiles on smooth roads

So, either way, you are screwed because you have your feet in two canoes.  Whichever way you lean, you will feel some pain.  It's your decision which pain is bearable to you.  It's up to you how you manage from hereon.

But isn't it nice to have this option.  Lot of people don't.  You are the lucky-sonofabitch.

Fact is:

If

1. If you come from affluent family, meaning you have house(s) and land(s) in Kathmandu
2. Through your family, you have substantial network, meaning you or your daddy has ties with thulo-badaa and knows the ropes
3. You got your US degree but can't get a job deserving your qualification

Then

It is best if you return to Nepal and make the best of what you already have.  Eg. some Golchas, Amatyas, Ranas, etc.

Or

If

1. If you come from middle class family with not much wealth and not much "afno manche" connections

Then

It is best to stay in the US or Australia and make something of yourself here.  You won't get better opportunity in Nepal than here.

Or

If

1. If you have PhD in STEM (Science, Technology, Engineering, Math) field from a respectable university
2. You already have or on track to get Green Card
3. You have a job that is actually quite fulfilling, meaning you enjoy doing what you do at work
4. You have kids

Then

Stay put in the US or Australia.  Nepal is not even an option for you.

And forget the crap about desh-bikaas and nation-building nonsense.  These are the guilt trips that people put on you. They have little or no concern about your well being.  

Say you do feel like nation building and return to Nepal leaving everything you have built here.  What exactly are you going to do or can you do?  Are you going to join the Maoists or Congressis or Communists?  Do you honestly think that you can rise high in those wretched ranks and be a prime minister or president?  Oh you say, you don't have to join the politics to do good in Nepal.  Sure, you say, you can open schools or another Maiti Nepal.  But, I say to you, you can do that by working in the US or Australia and sending some financial support back to Nepal.  You can designate people to do the ground work there.  That would be the most efficient use of the resources. YOU CAN SERVE YOUR MOTHERLAND FROM OUTSIDE TOO.

Focus on yourself and your family.  What is good for you?  What is good for your family?  And then, donate some to charity in Nepal with prudence.  If you can figure that out, nation will take care of itself.