Flow button IF Condition

jsantos489 

You could create multiple buttons instead and set those visibility individually.
Please have a close look at the column you refer to - those should be the internal names, not the display names.
e.g.:

{
  "$schema": "https://developer.microsoft.com/json-schemas/sp/column-formatting.schema.json",
  "elmType": "span",
  "style": {
    "color": "#0078d7",
    "display": "grid",
    "width": "180px"
  },
  "children": [
    {
      "elmType": "button",
      "style": {
        "border": "none",
        "background-color": "transparent",
        "color": "#0078d7",
        "cursor": "pointer",
        "display": "=if([$TipodeFicha] == 'Novo Fornecedor', 'block', 'none')"
      },
      "txtContent": "Fechar Pedido",
      "customRowAction": {
        "action": "executeFlow",
        "actionParams": "{\"id\": \"dd3debb9-ee20-4051-823f-c0f7252dfb44\"}"
      }
    },
    {
      "elmType": "button",
      "style": {
        "border": "none",
        "background-color": "transparent",
        "color": "#0078d7",
        "cursor": "pointer",
        "display": "=if([$TipodeFicha] != 'Novo Fornecedor', 'block', 'none')"
      },
      "txtContent": "processo de solicitação",
      "customRowAction": {
        "action": "executeFlow",
        "actionParams": "{\"id\": \"0X000000-123A-444-E11E-ABCDEFGHIJ\"}"
      }
    }
  ]
}

 
result:

Hope this helps, you can find further details and examples here:
https://pnp.github.io/List-Formatting/groupings/columntype/