You may see it on the attached movie.

I applied tick label formatter by chosing it from dropDown. It affected by width of new labels. But not by text. Formatter works like this: ((String -> String){ str -> "form" + str }) You may see, how I change upper bound value, and newly appeared labels are affected by that formatter.

Code:
import java.util.*;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Slider;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.StringConverter;

public class JavaCharts extends Application {

    public static void main(String[] args) {
        launch(args);
    }
    NumberAxis axis1 = new NumberAxis(0, 100, 10);
    NumberAxis axis2 = new NumberAxis(0, 100, 10);
    LineChart testedLineChart = new LineChart(axis1, axis2);
    VBox vb = new VBox();

    @Override
    public void start(Stage stage) throws Exception {
        testedLineChart.setTitle("LineChart");
        testedLineChart.setStyle("-fx-border-color: darkgray;");

        ObservableList list = FXCollections.observableArrayList();
        int max = 100;
        int min = 30;

        for (int i = 0; i < 30; i++) {
            XYChart.Data newData = new XYChart.Data();
            newData.setXValue(new Random().nextDouble() * (max - min) + min);
            newData.setYValue(new Random().nextDouble() * (max - min) + min);
            list.add(newData);
        }
        Object[] array = list.toArray();
        Arrays.sort(array, new Comparator() {

            @Override
            public int compare(Object t, Object t1) {
                return (int) Math.round(((Double) ((XYChart.Data) t).getXValue()) - ((Double) ((XYChart.Data) t1).getXValue()));
            }
        });

        XYChart.Series serie = new XYChart.Series("serie", FXCollections.observableArrayList(array));

        testedLineChart.getData().add(serie);

        Pane pane = new Pane();
        pane.setPrefSize(600, 600);

        Slider slider = new Slider(0, 1000, 10);
        slider.setPrefWidth(500);
        slider.valueProperty().bindBidirectional(axis2.upperBoundProperty());
        slider.setShowTickLabels(true);
        slider.setShowTickMarks(true);

        List<StringConverter<Number>> temp = new ArrayList<StringConverter<Number>>();
        temp.add(new NumberAxis().getTickLabelFormatter());
        temp.add(new ChartsLabelFormatter<Number>());

        ComboBox cb = new ComboBox();
        cb.getItems().addAll(temp);
        cb.valueProperty().bindBidirectional(axis2.tickLabelFormatterProperty());

        pane.setPrefSize(600, 600);
        pane.getChildren().add(testedLineChart);

        vb.getChildren().addAll(pane, slider, cb);

        Scene scene = new Scene(vb, 700, 700);
        stage.setScene(scene);
        stage.show();
    }

    private static class ChartsLabelFormatter<Number> extends StringConverter<Number> {

        @Override
        public String toString(Number t) {
            return "Form" + t;
        }

        @Override
        public Number fromString(String string) {
            throw new UnsupportedOperationException("Not supported yet.");
        }
    }
}

Chose commonFormatter from the dropDown of the comboBox in the bottom of the stage and after that start to move slider.