List of LISTS of tuples to Pandas dataframe?

Just flatten your list into a list of tuples (your initial list contains a sublists of tuples):

In [1251]: tupList = [[('commentID', 'commentText', 'date'), ('123456', 'blahblahblah', '2019')], [('45678', 'hello world', '2018'), ('0', 'text', '2017')]]

In [1252]: pd.DataFrame([t for lst in tupList for t in lst])
Out[1252]: 
           0             1     2
0  commentID   commentText  date
1     123456  blahblahblah  2019
2      45678   hello world  2018
3          0          text  2017

A shorter code this:

from itertools import chain
import pandas as pd

tupList = [[('commentID', 'commentText', 'date'), ('123456', 'blahblahblah', '2019')], [('45678', 'hello world', '2018'), ('0', 'text', '2017')]]

new_list = [x for x in chain.from_iterable(tupList)]
df = pd.DataFrame.from_records(new_list)

---

Edit

You can make the list comprehension directly in the from_records function.

tupList = [[('commentID', 'commentText', 'date'), ('123456', 'blahblahblah', '2019')], [('45678', 'hello world', '2018'), ('0', 'text', '2017')]]
print(pd.DataFrame(sum(tupList,[])))

Output

           0             1     2
0  commentID   commentText  date
1     123456  blahblahblah  2019
2      45678   hello world  2018
3          0          text  2017