To insert a Plotly chart in a view proceed as follows:

1.  Import plotly:

    import plotly

2.  Declare a text computed field like this:

        plotly_chart = fields.Text(
            string='Plotly Chart',
            compute='_compute_plotly_chart',
        )

3.  In its computed method do:

        def _compute_plotly_chart(self):
            for rec in self:
                data = [{'x': [1, 2, 3], 'y': [2, 3, 4]}]
                rec.plotly_chart = plotly.offline.plot(data,
                                             include_plotlyjs=False,
                                             output_type='div')

4.  In the view, add something like this wherever you want to display
    your plotly chart:

        <div>
            <field name="plotly_chart" widget="plotly_chart" nolabel="1"/>
        </div>