Problem with labels using library Charts with UIKit in XCode 12 - swift

Question

Hell my friends.I'm developing an app which has to show several charts using UIKit and the library Charts. I've been requested to use both things.
I have two arrays with correct data Ciudades y Precios.
Ciudades is String type and Precios Double type. I'v been reading how to use Charts library for hours but it seems that I dont understand how to use it because the chart I get it's not the one I excpected to. I need a chart with the cities on x label but they are not showed as you can see in the picture.
This is my code
class BarChartViewController: UIViewController, ChartViewDelegate {
#IBOutlet weak var barChartView: BarChartView!
var nombres: [String]!
var precios: [Double]!
override func viewDidLoad() {
super.viewDidLoad()
barChartView.delegate = self
nombres = eventos.devolverNombre()
print(nombres)
precios = eventos.devolverPrecios()
setChart(dataPoints: nombres, values: precios)
}
func setChart(dataPoints: [String], values: [Double]) {
barChartView.noDataText = "Es necesario añadir datos."
var dataEntries: [BarChartDataEntry] = []
for i in 0..<dataPoints.count {
let dataEntry = BarChartDataEntry(x: Double(i), y: values[i])
if dataEntry != nil {
dataEntries.append(dataEntry)}
}
let chartDataSet = BarChartDataSet(entries: dataEntries, label: "PRECIOS POR EVENTO")
let chartData = BarChartData(dataSet: chartDataSet)
chartDataSet.colors = [UIColor(red: 230/255, green: 126/255, blue: 34/255, alpha: 1)]
chartDataSet.colors = ChartColorTemplates.colorful()
barChartView.data = chartData
barChartView.xAxis.valueFormatter = DefaultAxisValueFormatter(block: {(index, _) in
return self.nombres[Int(index)] })
let labelCount = nombres.count
print(labelCount)
barChartView.xAxis.setLabelCount(labelCount, force: true)
barChartView.xAxis.labelRotationAngle = 90
barChartView.xAxis.centerAxisLabelsEnabled = true
barChartView.xAxis.labelPosition = .bottom
barChartView.xAxis.labelFont = UIFont.systemFont(ofSize: 10)
barChartView.animate(xAxisDuration: 1.0, yAxisDuration: 1.0, easingOption: .easeInBounce)
}
}