New to this! Looking for tips and critique please!

[buran]

Let's start by asking you not to use ALL CAPS - that's considered yelling.
Then some thoughts (not exhaustive list):

• You can use a data structure like dict, to get rid of these huge if statements
  
• Don't repeat yourself - define a function when you have repeating code
  
• when copy/paste code it's prone to error like the one on line 141 - you left team1wp, instead of changing it to team2wp
  
• use meaningful names instead of x and y
  
• don't use global variables, pass arguments to your functions.
  
• the checks you make on lines 7-15 will never be used - you have a while loop on line 3 and user input will always be forced to be a valid name. i.e. you cannot continue
  
• you don't give option for the user to stop when you ask to enter team2

so, something like this

teams =  {'Bucks': .815,
          'Raptors':.719,
          'Celtics':.672,
          'Heat':.631,
          'Pacers':.600,
          '76Ers':.600,
          'Nets':.469,
          'Magic':.462,
          'Wizards':.375,
          'Hornets':.354,
          'Bulls':.338,
          'Knicks':.318,
          'Pistons':.303,
          'Hawks':.299,
          'Cavaliers':.292,
          'Lakers':.769,
          'Clippers':.682,
          'Nuggets':.652,
          'Jazz':.636,
          'Thunder':.631,
          'Rockets':.631,
          'Mavericks':.588,
          'Grizzlies':.485,
          'Blazers':.448,
          'Spurs':.438,
          'Kings':.431,
          'Pelicans':.424,
          'Suns':.409,
          'Timberwolves':.297}

def get_team(teams):
    while True:
        user_response = input('Enter team name or stop to quit: ').title()
        if user_response == 'Stop':
            return None, None
        elif user_response in teams:
            return user_response, teams.get(user_response, 0)
        else:
            print('Invalid input')

def crtadv(home_team, home_power, home_coefficient, away_team, away_power, away_coefficient):
    if home_power * home_coefficient > away_power * away_coefficient:
        return home_team
    else:
        return away_team
        
game = []
for idx in range(2):
    team, power = get_team(teams)
    if team:
        game.append((team, power))
    else:
        break
else:
    home_team, away_team = game
    winner = crtadv(*home_team, 1.1, *away_team, .9)
    print(f"The winner will be the {winner}")