Why am I getting a cannot find symbol error in my factory class

Question

I'm trying to create a factory that contains chart types but I'm getting a cannot find symbol error on my this.map.put(chart.nc); under nc and I have no idea why, can anyone tell me what I'm doing wrong?

    private enum ChartType { BAR, PIE, LINE, SQUARE };
    private final Map<ChartType,DataComponent> map = new HashMap<>();

        public DataComponent createChart(ChartType chart){
            
             DataComponent nc = this.map.get(chart);
            
  
            if (nc == null){
                switch(chart){

                    case BAR: nc = new BarChart(); break;
                    case PIE: nc = new PieChart(); break;
                    case LINE: nc = new LineGraph(); break;
                    case SQUARE: nc = new SquareChart(); break;

                    }
                this.map.put(chart.nc);
            }
            return nc;
  }
 }