If there are more than 1000 rows, you should convert it to a SpatialDataFrame. You can do it like this:
df['SHAPE'] = df.apply(lambda row : arcgis.geometry.Geometry({'x': row['x'], 'y': row['y']}), axis=1 )
sdf = SpatialDataFrame(df)
layer = gis.content.import_data(sdf, title='My Data')
m.add_layer(layer) # add to map
find_nearest(layer, ...) # use for analysis