UPDATE

.inscode

-run = "cowsay 欢迎来到 InsCode"
+run = "make"
+
+entrypoint = "main.go"
 
 [nix]
 channel = "stable-22_11"

Makefile

+.PHONY: run
+run: main
+	./$<
+
+main: *.go go.mod
+	go build -o $@ .
+
+.PHONY: all
+all: main
\ No newline at end of file

go.mod

+module main
+
+go 1.19

inscode.nix

 { pkgs }: {
     deps = [
-        pkgs.cowsay
+        pkgs.go
+        pkgs.gopls
     ];
-}
+}
\ No newline at end of file

main.go

+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+	fmt.Println("Hello, World!")
+}