Can I call a view from within another view?

Without class based views:

def my_view(request):
    return call_another_view(request)

def call_another_view(request):
    return HttpResponse( ... )

With class based views:

def my_view(request):
    return CallAnotherView.as_view()(request)

class CallAnotherView(View):
    ...

View functions should return a rendered HTML back to the browser (in an HttpResponse). Calling a view within a view means that you're (potentially) doing the rendering twice. Instead, just factor out the "add" into another function that's not a view, and have both views call it.

def add_stuff(bar):
    item = Item.objects.create(foo=bar)
    return item

def specific_add_item_view(request):
    item = add_stuff(bar)
    ...

def big_view(request): 
    item = add_stuff(bar)
    ...

Sure, as long as when it's all said and done your view returns an HttpResponse object. The following is completely valid:

def view1(request):
    # do some stuff here
    return HttpResponse("some html here")

def view2(request):
    return view1(request)

If you don't want to return the HttpResponse from the first view then just store it into some variable to ignore:

def view1(request):
    # do some stuff here
    return HttpResponse("some html here")

def view2(request):
    response = view1(request)
    # do some stuff here
    return HttpResponse("some different html here")

A better way is to use the template system. Combining ideas from @Seth and @brady:

def specific_add_item_view(request, extra_context_stuff=None):
    Item.objects.create()
    context_variables = {} # obviously want to populate this
    if extra_context_stuff:
        context_variables.update(extra_context_stuff)
    return render(request, 'app_name/view1_template.html', context_variables)

def bigger_view(request):
    extra_context_stuff = {'big_view': True}
    return specific_add_item_view(request, extra_context_stuff)

And your app_name/view1_template.html might contain a conditional template tag

{% if big_view %}
<p>Extra html for the bigger view</p>
{% endif %}