How to correctly get the twig value
Looks like it should be 

{{ stream.node_title[0][0]['#context'].output }}


You can get the other two with 

{{ stream.node_title[0][1]['#context'].output }}
{{ stream.node_title[0][2]['#context'].output }}


But obviously this would be hard coded. To make all of this dynamic, you can loop.

{% for title in stream.node_title[0] %}
    {{ title['#context'].output }}
{% endfor %}