Here's the completed code:
```
# Import necessary modules
import nltk
from nltk.tokenize import sent_tokenize, word_tokenize
from collections import defaultdict
import matplotlib.pyplot as plt
# Create the defaultdict: ner_categories
ner_categories = defaultdict(int)
# Create the nested for loop
for sent in chunked_sentences:
for chunk in sent:
if hasattr(chunk, 'label'):
ner_categories[chunk.label()] += 1
# Create a list from the dictionary keys for the chart labels: labels
labels = list(ner_categories.keys())
# Create a list of the values: values
values = [ner_categories.get(v) for v in labels]
# Create the pie chart
plt.pie(values, labels=labels, autopct='%1.1f%%', startangle=140)
# Display the chart
plt.show()
```
The code uses a list comprehension to create a list called `values` by iterating over `labels` and using the `.get()`