Python code for Mad Libs
It is unnecessary to change the current directory in your python script. Instead you can just open the file with an absolute path - i.e. 

madLibFileObject = open("C:\\MyPythonScripts\\madLib.txt")`



To avoid leaking files (madLibFileObject), it it a good idea to use a with statement whenever you open a file, which takes care of automatically closing it for you:

with open("C:\\MyPythonScripts\\madLib.txt") as madLibFileObject:
     madLib = madLibFileObject.read()



Using three regular expressions that each match one word is overkill for this task. It is instead better to use word.lower() == "verb"

for word in madLib.split():
    newMadLib.append(word)
    if word.lower() == "verb":
        x = input('Enter VERB:  ')
        newMadLib[y] = x
    elif word.lower() == "noun":
        x = input('Enter NOUN:  ')
        newMadLib[y] = x
    elif word.lower() == "adjective":
        x = input('Enter ADJECTIVE:  ')
        newMadLib[y] = x


Then, there is clearly quite a bit of code duplication in the above loop, so it should be shortened using a list:

PARTS_OF_SPEECH = ["verb", "adjective", "noun"]
for word in madLib.split():
    if word.lower() in PARTS_OF_SPEECH:
        newMadLib[y] = input("Enter " + word.upper())



Your y counter variable is a reimplementation of the enumerate built-in function, in addition to being poorly named. index would be a better name:

for index, word in enumerate(madLib.split()):


Full code:

PARTS_OF_SPEECH = ["verb", "noun", "adjective"]
with open("C:\\MyPythonScripts\\madLib.txt") as madLibFileObject:
     madLib = madLibFileObject.read()
newMadLib = []
for index, word in enumerate(madLib.split()):
     if word.lower() in PARTS_OF_SPEECH:
        newMadLib[index] = input("Enter " + word.upper())
newMadLib = ' '.join(newMadLib)
print(madLib)
print(newMadLib)