Update: So after much pain and banging my head on my desk, I found a workaround to the problem I was having. In case anyone in the future has the same problem and comes across this post this is what worked for me: since I couldn't manipulate chart1 directly from the C++ side, but I could on the C# side, I simply added a rich textbox to the windows form, made it too small to see, hid it behind the chart, and used the
m_MyControl.GetControl()->richtextBox1->Text = " 1 2 \n 2 2 \n 3 3";
method to input data into the rich textbox I wanted put into the chart (C++ side). I then added an event handler on the C# side so that whenever the rich textbox was updated, the chart would parse the string, take that data, and plot it.
EDIT: Found the actual reason this wasn't working. Under project > properties > framework and references, I needed to add system.windows.forms.datavisualization so that VC++ knew where to find the member functions. Now I can call
m_ctrl1.GetControl()->chart1->Series[0]->Points->AddXY(0,0);
and it works just fine, adds the points to the graph and I am now a happy camper.