I have used the example of mikakaraila available on github as node-red-contrib-opcua library. The example flow code is:
[{"id":"a24729d8.6e3338","type":"tab","label":"Flow 1","disabled":false,"info":""},{"id":"a5c3b771.b035f","type":"ui_tab","z":"","name":"Home","icon":"dashboard","disabled":false,"hidden":false},{"id":"57e89fdc.43d9e","type":"ui_group","z":"","name":"Default","tab":"a5c3b771.b035f","disp":true,"width":"6","collapse":false},{"id":"30bfcadd.1595b6","type":"OpcUa-Endpoint","z":"","endpoint":"opc.tcp://TREL16087112.vstage.co:53530/OPCUA/SimulationServer","secpol":"None","secmode":"NONE","login":false},{"id":"9a453441.d77cc","type":"ui_base","theme":{"name":"theme-light","lightTheme":{"default":"#0094CE","baseColor":"#0094CE","baseFont":"-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif","edited":true,"reset":false},"darkTheme":{"default":"#097479","baseColor":"#097479","baseFont":"-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif","edited":false},"customTheme":{"name":"Untitled Theme 1","default":"#4B7930","baseColor":"#4B7930","baseFont":"-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif"},"themeState":{"base-color":{"default":"#0094CE","value":"#0094CE","edited":false},"page-titlebar-backgroundColor":{"value":"#0094CE","edited":false},"page-backgroundColor":{"value":"#fafafa","edited":false},"page-sidebar-backgroundColor":{"value":"#ffffff","edited":false},"group-textColor":{"value":"#1bbfff","edited":false},"group-borderColor":{"value":"#ffffff","edited":false},"group-backgroundColor":{"value":"#ffffff","edited":false},"widget-textColor":{"value":"#111111","edited":false},"widget-backgroundColor":{"value":"#0094ce","edited":false},"widget-borderColor":{"value":"#ffffff","edited":false},"base-font":{"value":"-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif"}},"angularTheme":{"primary":"indigo","accents":"blue","warn":"red","background":"grey"}},"site":{"name":"Node-RED Dashboard","hideToolbar":"false","allowSwipe":"false","lockMenu":"false","allowTempTheme":"true","dateFormat":"DD/MM/YYYY","sizes":{"sx":48,"sy":48,"gx":6,"gy":6,"cx":6,"cy":6,"px":0,"py":0}}},{"id":"715ed404.79906c","type":"ui_template","z":"a24729d8.6e3338","group":"57e89fdc.43d9e","name":"Browse","order":0,"width":"6","height":"11","format":"<div layout=\"row\" layout-align=\"space-between\">\n <select ng-model=\"item\" ng-options=\"items.item.displayName.text for items in msg.payload\">\n <option value=\"\">-- Objects Root --</option>\n </select>\n <button ng-click=\"send({payload: {actiontype: 'browse', root: item}})\">\n Browse\n </button>\n</div>\n<div layout=\"row\" layout-align=\"space-between\">\n <ul>\n <li ng-repeat=\"items in msg.payload\">\n {{items.item.displayName.text}}: {{items.item.nodeId}}\n </li>\n </ul>\n</div>\n","storeOutMessages":true,"fwdInMessages":false,"templateScope":"local","x":250.49998474121094,"y":81.80000305175781,"wires":[["3da8dc2e.9c9f3c","1a39131f.0bb62d"]]},{"id":"3da8dc2e.9c9f3c","type":"ui_toast","z":"a24729d8.6e3338","position":"top right","displayTime":"2","highlight":"","outputs":0,"ok":"OK","cancel":"","topic":"Browsing...","name":"Action","x":471.49998474121094,"y":82.59999084472656,"wires":[]},{"id":"1a39131f.0bb62d","type":"OpcUa-Browser","z":"a24729d8.6e3338","endpoint":"30bfcadd.1595b6","item":"","datatype":"","topic":"ns=0;s=85/0:Simulation","items":[],"x":250.9000244140625,"y":187.40000915527344,"wires":[["715ed404.79906c"]]}]
Just change the endpoint address and everything will work fine.
The mistake which I was doing is a small mistake but that will make your life much harder.
Never check this option. If you check it then it will pass the input which results in crashing and stopping your server because there will no input for browser node thus the template node.