Why you are entering the labels in the training step??!

[alaakh42]

In the examples/CoNLL 2002.ipynb directory the model uses the labels in the training step exactly in word2features function . and yet you got an accuracy less than 100%

[Pantamis]

In fact, the model solves NER and uses the postags which are given during training AND testing. The labels are B-MISC I-MISC O ... not NB V ADJ....

So yes the results are good but remain on a prelabelling or a POS tagger, which can't be always available. You may never reach such result without POS tags.