The best way to do this would be to take each of your sections, and give them each a function of their own. Also when its possible, separate user input functions from purely logic to improve readability!

For example, it could start looking like this..

def verify_pin(pin):
    if pin == '1234':
        return True:
    else:
        return False

def log_in():
    tries = 0
    while tries < 4:
        pin = input('Please Enter You 4 Digit Pin: ')
        if verify_pin(pin):
            print("Pin accepted!")
            return True
        else:
            print("Invalid pin")
            tries += 1
    print("To many incorrect tries. Could not log in")
    return False

def start_menu():
    print("Welcome to the atm!")
    if log_in():
        # you will need to make this one yourself!
        main_menu()
    print("Exiting Program")

start_menu()

Whenever you can avoid nesting, you should. This makes it easier to read.

In this case you can clearly see logging in will open the main_menu (which you will have to write), and entering a correct pin is the only way to log in.

The best way to do this would be to take each of your sections, and give them each a function of their own. Also, when it's possible, separate user input functions from purely logic to improve readability!

For example, it could start looking like this:

def verify_pin(pin):
    if pin == '1234':
        return True
    else:
        return False

def log_in():
    tries = 0
    while tries < 4:
        pin = input('Please Enter Your 4 Digit Pin: ')
        if verify_pin(pin):
            print("Pin accepted!")
            return True
        else:
            print("Invalid pin")
            tries += 1
    print("To many incorrect tries. Could not log in")
    return False

def start_menu():
    print("Welcome to the atm!")
    if log_in():
        # you will need to make this one yourself!
        main_menu()
    print("Exiting Program")

start_menu()

Whenever you can avoid nesting, you should. This makes it easier to read.

In this case you can clearly see logging in will open the main_menu (which you will have to write), and entering a correct pin is the only way to log in.